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After updating to Mono framework MDK 22.214.171.124 breakpoints were not working anymore in my Xamarin Mac project.
The breakpoints that were not working were in a PCL library. Breakpoints that I had in AwakeFromNib (main xamarin.mac project) function worked fine.
I don't know if the issue was related to PCL libraries or that the code were I wanted to break, was not executed on the Main UI thread.
After downgrading to Mono 4.8.1 everything worked fine again.
verified. same here.
Xamarin Studio Mac. no breakpoints working with Mono 126.96.36.199.
Visual Studio Preview Mac. limited breakpoints working.
I have downgraded to 4.8.1
Created attachment 22097 [details]
Test case (too simple) that does NOT show the issue
## Confirmation status
Not yet confirmed in a minimal Xamarin.Mac app, but this is quite possibly the same Xamarin Studio compatibility issue with the new portable PDB debugging format that I _have_ replicated with Xamarin.Android apps (Bug 56231, Comment 2). Visual Studio for Mac worked successfully for me for the Xamarin.Android project. (See below for some additional information about updating from Xamarin Studio to Visual Studio for Mac.)
## Steps attempted to replicate
1. Open the attached test case in Xamarin Studio.
2. Set a breakpoint on PortableLibrary1/MyClass.cs, line 12.
3. Build and run the application in the Debug configuration.
(This test case calls the method in MyClass.cs on a background thread.)
Xamarin Studio breaks successfully on PortableLibrary1/MyClass.cs line 12.
## Testing environment info (brief)
Xamarin Studio 6.3 (build 864) (6c2f673)
Mono 188.8.131.52 (2017-02/9667aa6) (64-bit)
Xcode 8.3 (12169), Build 8E162
US English locale, US Eastern time zone
This issue might be caused by the new portable PDB debugging file format used by Mono 5.0 and the rest of the Xamarin "15.2" release (https://releases.xamarin.com/stable-release-15-2/). Using Visual Studio for Mac with the Xamarin "15.2" release is strongly recommended. It is possible my attached test case is too simple to hit some newer part of the portable PDB format, and so it still works in the old Xamarin Studio version 6.3.
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 from . 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 desire, but as you found, it is not fully forwards-compatible with the new portable PDB debugging symbols file format used by Xamarin's "15.2 Release".
## Possible next steps
- The first recommended thing to try for any user seeing an issue with breakpoints in Xamarin Studio would be to update to Visual Studio for Mac.
- If the latest Stable channel version of Visual Studio for Mac shows the same issue, then if the original reporter or another user might by chance have a small Xamarin.Mac test case or some hints about how to modify the attached test case to replicate the issue, that would be excellent.
- Alternatively, if the attached test case fails for the original reporter, you can reply with that information too. In that case, the issue might depend some specific environment that does not quite match my local test environment.
Setting status to Assigned
With Visual Studio for Mac everything works fine.
breakpoints work about 20% of the time in Visual Studio Mac. the other 80% of the time nothing get hits. Yes, it is better than Xamarin Studio with 0% being hit. For some reason, Visual Studio Mac, iOS projects hit the breakpoints better than Android. still not always
I would use Xamarin Studio, but files do not want to be saved after changes and I lose hundreds of lines of code (it a known bug and told it being fixed)
With Visual Studio Professional the following is consistent:
Create basic Xamarin Forms app with PCL
Update Xamarin nuget packages to latest version
Insert breakpoint in App launch
Remote mac has xcode and VS for Mac installed
Android emulator hits breakpoint
iOS emulator hits breakpoint
iPhone debugging fails to hit breakpoint
Breakpoints don't work for me either in VS2017 neither for iOS nor for Android.
For Comment 9 and Comment 10,
> in VS2017
As a caution, note that this bug is filed against the "Xamarin Studio" product category in Bugzilla, and the original descriptions from Comment 0 and Comment 1 are discussing Xamarin Studio. If there are consistency issues with the debugger attachment in Xamarin Studio and Visual Studio for _Mac_, this bug will be focused on those issues on _Mac_.
For issues on Windows, I would recommend following other bugs. Bug 56225 appears to be one applicable report for Windows, and  appears to be another.
Xamarin Studio is not supported anymore, so you should switch to Visual Studio for Mac. If VS for Mac still has issues with breakpoints I'd need the about box information and the IDE log after such problem happens (you can get it using the Help -> Open Log Directory). Thanks!
*** Bug 56595 has been marked as a duplicate of this bug. ***
This is not fixed as of Mono 184.108.40.206
=== Visual Studio Community 2017 for Mac ===
Version 7.0.1 (build 24)
Installation UUID: b9d9479e-fe89-42b5-9c2b-4644399bb238
Mono 220.127.116.11 (2017-02/5077205) (64-bit)
GTK+ 2.24.23 (Raleigh theme)
Package version: 500010001
=== NuGet ===
=== .NET Core ===
Runtime: Not installed
SDK: Not installed
MSBuild SDKs: /Library/Frameworks/Mono.framework/Versions/5.0.1/lib/mono/msbuild/15.0/bin/Sdks
=== Xamarin.Profiler ===
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler
=== Apple Developer Tools ===
Xcode 8.3.2 (12175)
=== Xamarin.iOS ===
Version: 10.10.0.36 (Visual Studio Community)
Build date: 2017-05-22 16:30:53-0400
=== Xamarin.Android ===
Version: 18.104.22.168 (Visual Studio Community)
Android SDK: /Users/drew/Library/Developer/Xamarin/android-sdk-macosx
Supported Android versions:
4.4 (API level 19)
4.4.87 (API level 20)
5.0 (API level 21)
5.1 (API level 22)
6.0 (API level 23)
7.0 (API level 24)
7.1 (API level 25)
SDK Tools Version: 26.0.2
SDK Platform Tools Version: 25.0.6
SDK Build Tools Version: 25.0.3
Java SDK: /usr
java version "1.8.0_101"
Java(TM) SE Runtime Environment (build 1.8.0_101-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.101-b13, mixed mode)
Android Designer EPL code available here:
=== Xamarin Inspector ===
Build date: Fri, 21 Apr 2017 17:57:12 GMT
=== Xamarin.Mac ===
Version: 22.214.171.124 (Visual Studio Community)
=== Build Information ===
Release ID: 700010024
Git revision: 7ab1ca2ced6f584e56b7a0d4d321d00775cd95c9
Build date: 2017-05-19 05:44:51-04
Xamarin addins: 08d17158f3365beee5e60f67999e607cce4b3f93
Build lane: monodevelop-lion-d15-2
=== Operating System ===
Mac OS X 10.12.5
Darwin 16.6.0 Darwin Kernel Version 16.6.0
Fri Apr 14 16:21:16 PDT 2017
Created attachment 22560 [details]
going research today.
seems to be PCL projects are not working with breakpoints. found a few things on the forums to try today. I report back later.
Any engineer is welcome to remotely connect to my computer and troubleshoot the issue.
Can someone who has this problem attach YourPclProjectName.dll and YourPclProjectName.pdbb file from bin/Debug folder?
Also try updating Xamarin.Forms to latest stable version(126.96.36.199).
If anyone can still reproduce this please read Comment 18 and 19.