App-V 4 Application Troubleshooting: Breaking Down Virtualization Issues Pt. I

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If you are working with an application that has been virtualized with App-V 4.x and that application is not functioning as expected, one of the first steps in troubleshooting should always be to try to determine if the issue is related to sequencing or related to virtualization. For the standard application, Devirtualization is pretty straight-forward and pointed out in the following article:

https://blogs.technet.com/b/gladiatormsft/archive/2013/10/26/appv-on-devirtualization.aspx

One you have determined that the issue is likely a virtualization issue (done by successfully de-virtualizing using the article above) then you can proceed to quickly troubleshoot the issues further using a variety of approaches. One good source for V 4 troubleshooting is John Behneman’s post on the App-V team blog: https://blogs.technet.com/b/appv/archive/2012/11/14/3494514.aspx

You can also take this further by enabling the SFTLDR unhandled exception log (SFTLDR.LOG) which tracks hidden errors within the SFTLDR hook DLL which is the most critical virtualization DLL.

To enable the SFTLDR.LOG, create a string (REG_SZ) value called UnhandledExceptionFilterLocation within the following registry key: HKLM\SOFTWARE\Microsoft\SoftGrid\4.5\SystemGuard

For the Value data, you will want to put in the path to an existing directory that is at least one level deep from the root of the drive (i.e. C:\\TEMP\\SFTLDR.LOG.) Also note that I have to double the slash count for paths.

The SFTLDR.LOG file looks like this:

 

 [08/27/2014 18:21:26.379] [03ac] [0a38] [Q:\KK_HAWT.BTY\LISTA\RUN\FIRST\hail.exe] HookedLoadLibraryExW. lpLibFileName=Q:\KK_HAWT.BTY\LISTA\RUN\FIRST\test.dll

 [08/27/2014 18:21:26.379] [03ac] [0a38] [Q:\KK_HAWT.BTY\LISTA\RUN\FIRST\hail.exe] HookedLoadLibraryExW: SXS start

 [08/27/2014 18:21:26.379] [03ac] [0a38] [Q:\KK_HAWT.BTY\LISTA\RUN\FIRST\hail.exe] HookedLoadLibraryExW: No mapping for Q:\KK_HAWT.BTY\LISTA\RUN\FIRST\test.dll

 [08/27/2014 18:21:26.410] [03ac] [0a38] [Q:\KK_HAWT.BTY\LISTA\RUN\FIRST\hail.exe] HookedLoadLibraryExW: LoadLibrary failed (1). dwLastError=14001