Monodevelop crashing on script open -- 4.1.2-4.1.5

Tried a bunch of solutions from the forums, but I'm still getting this error every time I open Monodevelop and try to edit a script. Doesn't seem project specific -- other people can work with the same scripts -- but I can't seem to find a solution for my machine running Win7x64. It started with an occasional crash, now happens every time. Reinstalled Unity several times, versions 4.1.2 through 4.1.5. Anyone come across something like this?

 System.NotSupportedException: The given path's format is not supported.
 
    at System.Security.Util.StringExpressionSet.CanonicalizePath(String path, Boolean needFullPath)
 
    at System.Security.Util.StringExpressionSet.CreateListFromExpressions(String[] str, Boolean needFullPath)
 
    at System.Security.Permissions.FileIOPermission.AddPathList(FileIOPermissionAccess access, AccessControlActions control, String[] pathListOrig, Boolean checkForDuplicates, Boolean needFullPath, Boolean copyPathList)
 
    at System.Security.Permissions.FileIOPermission..ctor(FileIOPermissionAccess access, String[] pathList, Boolean checkForDuplicates, Boolean needFullPath)
 
    at System.IO.Path.GetFullPath(String path)
 
    at MonoDevelop.Core.FilePath.get_CanonicalPath() in c:\BuildAgent\work\f07246b5212f7be4\monodevelop\main\src\core\MonoDevelop.Core\MonoDevelop.Core\FilePath.cs:line 81
 
    at MonoDevelop.VersionControl.Git.GitRepository.<>c__DisplayClass1.<GetDirectoryVersionInfo>b__0(IEnumerable`1 files, VersionStatus fstatus) in c:\BuildAgent\work\f07246b5212f7be4\monodevelop\main\src\addins\VersionControl\MonoDevelop.VersionControl.Git\MonoDevelop.VersionControl.Git\GitRepository.cs:line 281
 
    at MonoDevelop.VersionControl.Git.GitRepository.GetDirectoryVersionInfo(FilePath localDirectory, IEnumerable`1 localFileNames, Boolean getRemoteStatus, Boolean recursive) in c:\BuildAgent\work\f07246b5212f7be4\monodevelop\main\src\addins\VersionControl\MonoDevelop.VersionControl.Git\MonoDevelop.VersionControl.Git\GitRepository.cs:line 290
 
    at MonoDevelop.VersionControl.Git.GitRepository.OnGetDirectoryVersionInfo(FilePath localDirectory, Boolean getRemoteStatus, Boolean recursive) in c:\BuildAgent\work\f07246b5212f7be4\monodevelop\main\src\addins\VersionControl\MonoDevelop.VersionControl.Git\MonoDevelop.VersionControl.Git\GitRepository.cs:line 219
 
    at MonoDevelop.VersionControl.Repository.GetDirectoryVersionInfo(FilePath localDirectory, Boolean getRemoteStatus, Boolean recursive) in c:\BuildAgent\work\f07246b5212f7be4\monodevelop\main\src\addins\VersionControl\MonoDevelop.VersionControl\MonoDevelop.VersionControl\Repository.cs:line 190
 
    at MonoDevelop.VersionControl.VersionControlNodeExtension.GetVersionInfo(Repository vc, FilePath filepath, Object dataObject, Boolean allowCacheMiss) in c:\BuildAgent\work\f07246b5212f7be4\monodevelop\main\src\addins\VersionControl\MonoDevelop.VersionControl\MonoDevelop.VersionControl\VersionControlNodeExtension.cs:line 176
 
    at MonoDevelop.VersionControl.VersionControlNodeExtension.<>c__DisplayClass3.<BuildNode>b__0(Object x) in c:\BuildAgent\work\f07246b5212f7be4\monodevelop\main\src\addins\VersionControl\MonoDevelop.VersionControl\MonoDevelop.VersionControl\VersionControlNodeExtension.cs:line 92
 
    at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
 
    at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
 
    at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
 
    at System.Threading.ThreadPoolWorkQueue.Dispatch()
 
    at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()