Help us debug Sumatra hangs or crashes
If Sumatra crashes or hangs reliably on your machine but we can’t reproduce it ourselves, you can help us by debugging it. Here’s a tutorial on how to do it.
Please first test with latest pre-release version from https://www.sumatrapdfreader.org/prerelease.html
Some bugs might already be fixed there compared to latest
Those instructions require SumatraPDF 3.2 or later.
Getting logs #
We log information that might be helpful in diagnosing issues.
This saves logs to a file and opens default editor for
.txt files with log file.Install necessary software #
- Install WinDBG debugger from Microsoft Store at https://www.microsoft.com/en-us/p/windbg-preview/9pgjgd53tn86#activetab=pivot:overviewtab. Alternatively, you can follow instructions from https://docs.microsoft.com/en-us/windows-hardware/drivers/debugger/debugger-download-tools
- In SumatraPDF, use menu
Debug/Download symbols. Symbols are important for the debugger (like WinDBG) to resolve addresses to names that
First, vocabulary.
%ProgramFiles% means the standard directory where Windows installs programs. It’s c:\Program Files on 32-bit Windows and c:\Program Files (x86) on 64-bit Windows.Debugging a crash #
To debug crashes:
- start SumatraPDF.exe under the control of WinDBG
- start WinDBG.exe
- File/Open (Ctrl-E), find and open SumatraPDF.exe executable
- In WinDBG, type:
.sympath+ SRV*c:\symbols*https://msdl.microsoft.com/download/symbolsg
- when Sumatra crashes, type:
!analyze -vand paste the result of that to the bug report
Debugging a hang #
Here are the steps to follow if Sumatra hangs
- Start SumatraPDF.exe and get it to hang
- start WinDBG.exe
- use File/Attach to process (F6) and select SumatraPDF.exe from the
- In WinDBG, type:
.sympath+ SRV*c:\symbols*https://msdl.microsoft.com/download/symbols~*kblmf
Attach the output to bug report.