pdb file, check for insufficient disk space, invalid path, or insufficient privilege

The culprit was deleaker that I had installed to detect memory leak and it looks like it was holding up the debugger/pdb files. After uninstalling my problem is fixed.

I have faced similar problem when I worked with single pdb file in two Visual Studio versions. Closing one visual studio version solved the problem.

It worked for me when I closed ProcessExplorer (sysinternal tool procexp64.exe) which I was using to check number of thread memory usage. Search that file and then close it.

[Update]: You can also use Windows "Task Manager" as efficiently as "Process Explorer of Sysinternal" to locate any zombie handles. Task Manager | Performance | Open Resource Monitor | CPU |Associated Handles | search ->