Category Archives: Mono Framework

Common issues from the Xamarin 15.2 release being tracked by the Xamarin team

In case it might be useful for reference, here is an in-progress list of some commonly seen issues being tracked by the Xamarin team for the Xamarin 15.2 release. The list is sorted approximately by the number of users subscribed to each bug report, and in some cases also by additional hand-tallying. The list focuses on issues where the pattern of reports suggests a change in behavior compared to the Xamarin 15.1 release. This list is not exhaustive: It does not include every issue user-submitted issue reported since the time of the Xamarin 15.2 release.

  • Bug 56275 and developercommunity 54945 [Xamarin.VisualStudio] Significant increase in the chances of hitting “Unable to copy file “obj\Debug\App1.dll” to “bin\Debug\App1.dll”. The process cannot access the file ‘bin\Debug\App1.dll’ because it is being used by another process.” and “Exceeded retry count of 10. Failed”. Under investigation.
    • A few possible temporary workarounds are discussed on the bug report.
    • One comment on the report also indicates that installing and using the Visual Studio 2017 Preview version 15.3 might resolve the issue.
  • Bug 56246 [Mono, Xamarin.Android, Xamarin.iOS, Xamarin.Mac] Tracking bug for upstream Roslyn issue 17934: “error MSB6006: “csc.exe” exited with code 1″ due to KeyNotFoundException when compiling projects that include async partial methods. Integration of the upstream Roslyn fix is in-progress.
    • Partial temporary workaround: Switch back to mcs and xbuild (see additional details below).
  • Bug 56213 [Xamarin.VisualStudio] “Can not resolve reference: C:/Windows/Microsoft.NET/Framework/v4.0.30319/de/mscorlib.resources.dll” when building or breakpoints fail to hit on iOS devices when debugging. Now RESOLVED in the source code, and will be included in an upcoming release.
  • Bug 55087 [Xamarin.Android] “System.NotSupportedException: Stack walks are not supported on this platform – System.Reflection.MethodBase.GetCurrentMethod” when attempting to debug on x86_64 Android emulators. Now RESOLVED in the source code, and will be included in an upcoming release.
    • Partial temporary workaround: Use an x86 Android emulator rather than an x86_64 Android emulator.
  • Bug 56296 [Xamarin.Forms] “MTOUCH: error MT2001: Could not link assemblies.” when attempting to link Xamarin.Forms projects that use XamlC on iOS because XamlC does not update the new default portable .pdb debug symbol files. Now RESOLVED in the source code, and will be included in an upcoming release of Xamarin.Forms.
    • Possible temporary workaround: Disable XamlC.
    • Alternate possible temporary workaround: Switch back to mcs and xbuild (see additional details below).
  • Bug 56240 [Xamarin.Android] Performance degradation when using System.Linq.Expressions in Xamarin.Android 7.3. A candidate change has been added and will be included in an upcoming release of Xamarin.Android.
  • Bug 56238 and developercommunity 49033 [Xamarin.Android] App exits on launch or fails to hit breakpoints when debugging due to change in default build behavior when the Optimize MSBuild property is not explicitly set. Now RESOLVED in the source code, and will be included in an upcoming release.
    • Workaround: Explicitly set the Optimize property to False in the .csproj file. See the answer on the developercommunity item for a few additional details.
  • Compatibility change: [Xamarin Studio] Breakpoints no longer work for certain Xamarin project types and scenarios in Xamarin Studio 6.3 due incomplete support for the new default portable .pdb format generated by Mono 5.0.
    • Recommended solution: Install and use Visual Studio for Mac now that it is generally available and the recommended environment for Xamarin development on Mac.
    • Alternate possible temporary workaround: Switch back to mcs and xbuild (see additional details below).
  • Bug 56192 [Xamarin.VisualStudio] MultiDex is disabled after saving changes to Xamarin.Android project due to incorrect MSBuild property name <AndroidEnableMultipleDex>. Now RESOLVED in the source code, and will be included in an upcoming release.
    • Workaround: In the .csproj file, replace all occurrences of AndroidEnableMultipleDex with the correct property name AndroidEnableMultiDex using a text editor.
  • Bug 56220 [Xamarin.iOS, Xamarin.VisualStudio] “The item “C:….nuget\packages\Autofac\4.5.0\lib\netstandard1.1\Autofac.dll” in item list “ReferenceCopyLocalPaths” does not define a value for metadata “ResolvedFrom””. Under investigation. A few possible temporary workarounds are discussed on the bug report.
    • A possible temporary workaround is mentioned on the bug report.

Temporarily switching back to mcs and xbuild

The Xamarin 15.2 release includes Mono 5.0, which enables the Roslyn csc C# compiler by default and deprecates the use of xbuild in favor of msbuild. For the Xamarin toolchain, this adds C# 7 support and changes the default debugging symbol format from .mdb files to portable .pdb files. And Visual Studio for Mac uses msbuild by default when building projects.

The change from mcs to csc and xbuild to msbuild is related to several of the issues listed above. One potential workaround in those cases is to switch back to the earlier combination of mcs and xbuild without downgrading Mono or the Xamarin toolchain. As a caution, this is not a tested scenario, so although this approach has been reported to work well so far, it does still have a chance of hitting other secondary errors.

  1. Add the following PropertyGroup element to the bottom of the .csproj file for your app project just before the closing </Project> tag:
    <PropertyGroup Condition=" '$(OS)' == 'Unix' ">
        <CscToolExe>mcs.exe</CscToolExe>
    </PropertyGroup>
    
  2. Disable Visual Studio > Preferences > Build > Build with MSBuild instead of xbuild.(This setting is also available in Xamarin Studio 6.3. It is disabled by default in Xamarin Studio, but some users might have enabled it by hand in the past.)
  3. Close and reopen the solution to ensure the new setting is used.
  4. Clean and rebuild the project.

Alpha Release: 15.3 Preview 1

UPDATE (2017-05-11): We are releasing a Hotfix for Visual Studio for Mac. This new version (7.1.0.583) resolves the issue mentioned here.

We are releasing the first Alpha preview of our next major release, called 15.3. This release includes our next preview of Visual Studio for Mac.

As this is an Alpha build, there are some known issues and the possibility of new issues being found during testing. Of course, additional bug reports are still welcome for these preview versions. If you see any suspicious behavior that you wish to report, please file a quick bug.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.

Please check out the product release notes to see all the fixes and known issues for this release.


Products Released


Installing the Alpha and switching back to Stable

You can install this new Alpha version or switch back to the current Stable version by changing updater channels.


Upcoming Release Dates

Alpha 1 – This Release!

 

Stable Release: 15.2

We are releasing the Stable build of our next major release, called 15.2 to the Alpha, Beta, and Stable channels.

This release is now available in the Xamarin updater channels and as part of the May 10th – version 15.2 update for Visual Studio 2017.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.


Updating from Xamarin Studio to Visual Studio for Mac

As announced at the Microsoft Build conference, Visual Studio for Mac is now generally available. It is the recommended environment for Xamarin developers on Mac moving forward. Visual Studio for Mac has all the features of Xamarin Studio, adds cloud and web development, and contains improvements for cross-platform mobile development.

To get started with Visual Studio on Mac, download and run the Visual Studio for Mac installer. It will leave Xamarin Studio unchanged, update the other Xamarin packages to the current versions, and install the Visual Studio for Mac app. Xamarin Studio can continue to be used alongside Visual Studio for Mac if desired, but please note that debugging symbols in this 15.2 release are not backwards compatible with Xamarin Studio 6.3, so you will need to use Visual Studio for Mac to hit breakpoints and break where expected on unhandled exceptions.


Known Issues

There are some known issues and the possibility of new issues being found. Additional bug reports are still welcome for this stable version. If you see any suspicious behavior that you wish to report, please file a quick bug.

Please check out the product release notes to see all the fixes and known issues for this release.

Update for May 17: See also the list of commonly reported issues from the Xamarin 15.2 release being tracked by the Xamarin team.

  • [Android SDK Manager]55943 – “The “Aapt” task failed unexpectedly”, “Error creating start-server process”, or other errors after updating Android tools via Xamarin’s Android SDK Manager due to incorrect file permissions that cause “Native error= Access denied” for various executables.
    • Manual workaround: Add the executable flag to the “ApplicationName” indicated in the log file that is missing the executable flag, for example by using chmod in a Terminal.app command prompt.
  • [Android SDK Manager] 55720 – On uninstalling Latest build of SDK Tools, All SDK tools are uninstalled.
    • A candidate fix will be included in an upcoming preview of Visual Studio for Mac.

Products Released


Installing

You can get this latest version by checking for updates on the Stable updater channel and in Visual Studio 2017 by installing Visual Studio 2017 version 15.2.


Previous Versions for Visual Studio 2015 or Mac-only

Previous Versions for Visual Studio 2017

  • For Windows the previous versions and download locations are:

(Note that the previous available version of Visual Studio 2017 is the RTW version 15.0 rather than the 15.1 update to follow the Visual Studio update guidelines.)


Upcoming Release Dates

Alpha 1 – April 6th 2017

Alpha 2 – April 11th 2017

Alpha 3 – April 19th 2017

Beta 1 – April 25th 2017

Beta 2 – May 3rd 2017

Stable – This Release!

Beta Release: 15.2 Preview 2

 

We are releasing the second Beta preview of our next major release, called 15.2. This release includes our next preview of Visual Studio for Mac.

Using the latest Visual Studio for Mac Preview 10 with this release is encouraged, but you can also continue to use Xamarin Studio if you prefer (though new previews of XS are not included in this release). If you are updating from Visual Studio for Mac Preview 5 or earlier, you’ll need to check for updates once to install the new Preview and then once more to get the new Xamarin Platform components. It should be noted that since VS for Mac is still in preview, it is not yet a fully supported product.

These latest Beta versions are now also available in Visual Studio 2017 Preview as part of the May 3 update (26430.01 – Preview).  The Xamarin.VisualStudio extension 4.5.0.439 in this Visual Studio 2017 Preview is one small edit behind the version in VS 2015.

As this is a Beta/Preview build, there are some known issues and the possibility of new issues being found during testing. Of course, additional bug reports are still welcome for these preview versions. If you see any suspicious behavior that you wish to report, please file a quick bug.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.

Please check out the product release notes to see all the fixes and known issues for this release.


Products Released


Installing the Beta and switching back to Stable

You can install this new Beta version or switch back to the current Stable version by changing updater channels.


Upcoming Release Dates

Alpha 1 – April 6th 2017

Alpha 2 – April 11th 2017

Alpha 3 – April 19th 2017

Beta 1 – April 25th 2017

Beta 2 – This Release!

Beta Release: 15.2 Preview 1

We are releasing the first Beta preview of our next major release, called 15.2. This release includes our next preview of Visual Studio for Mac.

Using the latest Visual Studio for Mac Preview 9 with this release is encouraged, but you can also continue to use Xamarin Studio if you prefer (though new previews of XS are not included in this release). If you are updating from Visual Studio for Mac Preview 5 or earlier, you’ll need to check for updates once to install the new Preview and then once more to get the new Xamarin Platform components. It should be noted that since VS for Mac is still in preview, it is not yet a fully supported product.

These latest Beta versions are now also available in Visual Studio 2017 Preview as part of the April 26 update (26424.02 – Preview).

This Beta release also includes an updated Xamarin Studio 6.3.0.864 build that notifies users that Visual Studio for Mac Preview is now available: “Visual Studio for Mac is Microsoft’s fully-featured IDE for developers on Mac. It has all the features of Xamarin Studio, adds cloud and web development, and contains improvements for cross-platform mobile development. Try the preview and let us know what you think!”

As this is a Beta build, there are some known issues and the possibility of new issues being found during testing. Of course, additional bug reports are still welcome for these preview versions. If you see any suspicious behavior that you wish to report, please file a quick bug.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.

Please check out the product release notes to see all the fixes and known issues for this release.


Products Released


Installing the Beta and switching back to Stable

You can install this new Beta version or switch back to the current Stable version by changing updater channels.


Upcoming Release Dates

Alpha 1 – April 6th 2017

Alpha 2 – April 11th 2017

Alpha 3 – April 19th 2017

Beta 1 – This Release!

Alpha Release: 15.2 Alpha Preview 3

We are releasing the third Alpha preview of our next major release, called 15.2. This release includes our next preview of Visual Studio for Mac.

Using the latest Visual Studio for Mac Preview 8 with this release is encouraged, but you can also continue to use Xamarin Studio if you prefer (though new previews of XS are not included in this release). If you are updating from Visual Studio for Mac Preview 5 or earlier, you’ll need to check for updates once to install the new Preview and then once more to get the new Xamarin Platform components.

New: This Xamarin release is now also available in Visual Studio 2017 Preview as part of the April 20 update (26419.01 – Preview).

As this is an Alpha build, there are some known issues and the possibility of new issues being found during testing. Of course, additional bug reports are still welcome for these preview versions. If you see any suspicious behavior that you wish to report, please file a quick bug.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.

Please check out the product release notes to see all the fixes and known issues for this release.


Products Released


Installing the Alpha and switching back to Stable

You can install this new Alpha version or switch back to the current Stable version by changing updater channels.


Upcoming Release Dates

Alpha 1 – April 6th 2017

Alpha 2 – April 11th 2017

Alpha 3 – This Release!

Alpha Release: 15.2 Alpha Preview 2

We are releasing the second Alpha preview of our next major release, called 15.2.

Using the latest Visual Studio for Mac Preview 7 with this release is encouraged, but you can also continue to use Xamarin Studio if you prefer (though new previews of XS are not included in this release). If you are updating from Visual Studio for Mac Preview 5 or earlier, you’ll need to check for updates once to install the new Preview and then once more to get the new Xamarin Platform components.

Note that this preview version is not yet available in Visual Studio 2017. This post will be updated within the next couple of days with the steps to try this release in Visual Studio 2017.  Edit: Unfortunately some new complications came up with the packaging process for Visual Studio 2017. Work is underway to resolve those issues, but in the mean time, if you use Xamarin.iOS in Visual Studio 2017, be sure to hold off for now on trying the preview versions on the Mac. (Otherwise you will run into some incompatibility errors such as “The root assembly … conflicts with another assembly”.) The Visual Studio Preview version 15.2 (26412.01) from April 17 does not yet include the Xamarin 15.2 Alpha preview component.

As this is an Alpha build, there are some known issues and the possibility of new issues being found during testing. Of course, additional bug reports are still welcome for these preview versions. If you see any suspicious behavior that you wish to report, please file a quick bug.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.

Please check out the product release notes to see all the fixes and known issues for this release.


Products Released


Installing the Alpha and switching back to Stable

You can install this new Alpha version or switch back to the current Stable version by changing updater channels.


Upcoming Release Dates

Alpha 1 – April 6th 2017

Alpha 2 – This Release!

Security update for the libjpeg information disclosure vulnerability for Mono Framework

We are releasing a security update to the Mono Framework to address an information disclosure vulnerability in libjpeg.

For more details on this security vulnerability, please see KB 4019460 .

If you observe any problematic behavior that you wish to report, please file a quick bug.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.

Please check out the product release notes to see all the fixes and known issues for this release.


Products Released


 

 

Alpha Release: 15.2 Alpha Preview 1

We are releasing the first Alpha preview of our next major release, called 15.2.

This initial Alpha release currently only includes updates for Mac and is not compatible with the existing Stable Xamarin version in Visual Studio on Windows. So for the moment please only try this Alpha version if you do all your development work on Mac. Keep an eye on this post for updates about the corresponding Windows updates soon.

Using the latest Visual Studio for Mac Preview 6 with this release is encouraged, but you can also continue to use Xamarin Studio if you prefer. If you are updating an earlier Visual Studio for Mac Preview, you’ll need to check for updates once to install Preview 6 and then once more to get the new Xamarin Platform components.

As this is an Alpha build, there are some known issues and the possibility of new issues being found during testing. Of course, additional bug reports are still welcome for these preview versions. If you see any suspicious behavior that you wish to report, please file a quick bug.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.

Please check out the product release notes to see all the fixes and known issues for this release.


Products Released


Installing the Alpha and switching back to Stable

You can install this new Alpha version or switch back to the current Stable version by changing updater channels.


Upcoming Release Dates

Alpha 1 – This Release!

Stable Release: 15.1

We are releasing the Stable build of our next major release, called 15.1 to the Alpha, Beta, and Stable channels.  The 15.1 release name follows the Microsoft VS release naming convention.

This release is now available in the Xamarin updater channels and as part of the April 5th update for Visual Studio 2017.

If you notice an error in this blog post or have trouble downloading one of the installer packages, please let us know in the corresponding forum thread.


Known Issues

There are some known issues and the possibility of new issues being found. Additional bug reports are still welcome for this stable version. If you see any suspicious behavior that you wish to report, please file a quick bug.

Please check out the product release notes to see all the fixes and known issues for this release.

  • [Xamarin.VS]54465 – Object reference not set to an instance of an object when building Master Detail Forms Shared iOS project template.
    • The current workaround is to rebuild the solution again. Please stay tuned for resolution details.
  • [Xamarin Studio]53906 – Fastlane showing nothing from Apple subscriptions and not updating.
    • The team details dialog is empty. In certain scenarios signing identities and provisioning profiles are not displayed, even if they are installed and valid on the users machine. We will continue working on this issue, and expect to publish a fix into the Xamarin Alpha, Beta and Stable channels soon.

Products Released


Installing

You can get this latest version by checking for updates on the Stable updater channel and in Visual Studio 2017 by installing Visual Studio 2017 15.1 (26403.00).


Previous Versions

  • For Mac the previous versions are: Xamarin Studio 6.2.1.3, Xamarin.iOS 10.6.0.10, Xamarin.Android 7.2.0-7, and Xamarin Profiler 1.2.1.
  • For Windows the previous versions are: Xamarin.VisualStudio 4.3.0.795, Visual Studio 2017 15.0, Xamarin Studio 6.2.0.1829, and Xamarin Profiler 1.2.1.

Previous Xamarin versions can be found on the Xamarin account page as described in the article about older Xamarin versions. Previous versions of the Xamarin Profiler can be found in the Xamarin Profiler release notes. Previous versions of Visual Studio 2017 can be found on My.VisualStudio.com as described in the article about older Visual Studio versions.


Upcoming Release Dates

Alpha 1 – March 1st 2017

Alpha 2 – March 7th 2017

Beta 1 – March 16th 2017

Beta 2 – March 27th 2017

Stable – This Release!