Error MSB6006: “mt.exe” exited with code 31

Question

I ran into this problem today while migrating a VS2008 solution to VS2010. The problem occurred in either of the following scenarios:

1. Rebuild Solution

Answer 1

Look for an MSB8012 warnings. Likely you have a different output specification for the C++ output value and the Linker Output value.

Answer 2

I have a project (*.sln) written in visual studio c 8.0. It was migrated to VC10 recently. When I choose the "Release mode", it was compiled sucessfully. But if I choose "Debug mode", the error " MSB6006 mt.exe code 31" happened.

I found that, in the debug mode, it used a wrong sub-project to startup. After fixing the startup sub-project, it goes fine so far.

---- new status --- This won't fix the problem. It just makes the problem disapear temporalily by rebuilding-all. Also, there are other faults caused by the migration. The "resources.h" is missed from the new project and the "winres.rc" is shorten.

Answer 3

Run VS as administrator. It solved the problem for me.

Answer 4

Check if you have any anti-virus software like AVG. Exclude the manifest files in the anti-virus software exclusion list.

Answer 5

In my projects, the Intermediate and Output directories were set to:

• Intermediate Dir : $(Configuration)\
• Output Dir : $(SolutionDir)bin\$(Configuration)\

Under C/C++-->Output Files, I had the following:

• ASM List Location : $(IntDir)\
• Object File Name : $(IntDir)\
• Program Database File Name : $(OutDir)\$(TargetName).pdb

Under Linker-->Manifest File, I had:

• Manifest File : $(IntDir)$(TargetName)$(TargetExt).intermediate.manifest

---

The cure was to remove the trailing \ from my C/C++-->Output Files section (because it's already part of those variables):

• ASM List Location : $(IntDir)
• Object File Name : $(IntDir)
• Program Database File Name : $(OutDir)$(TargetName).pdb

Normally, the double-up of using $(IntDir) or $(OutDir) with a trailing \ doesn't seem to cause trouble, even though it's bad practice. I can't remember now whether I did it by accident or if the conversion process did it, but for whatever reason, it seems to have been messing up MT.exe.

I hope this is useful to anyone else who encounters this problem. Your settings may well be different, but consider that it may be related to improperly formed filenames.