TFS - Undo a Resolve Conflict During a Merge

Scope

Merge from projA to projB

Our IDE is Visual Studio 2013 and we use Visual Studio Online TFS as our repository.

As our projects grow in omni-direction with developments going on in multiple branches in TFS, I was trying to perform a merge between 2 projects and had some problems in trying to undo resolved conflicts. After I resolved the conflicts and before I commit any changes, there is no option for me to undo any resolved conflicts.

Furthermore, I have also tried the following and none worked for me. Visual Studio still assumes conflicts are resolved even though I did not check in anything.

• Undo Pending Changes then Merge again. 
• Delete the working folder, Get Latest then Merge again.
• Use a different version of Visual Studio then Merge.
• Shelve changes and Merge again.
• Delete the working folder. Create a new Workspace with different local folder mapping.
• Repair (reinstall) Visual Studio.
• Login with a different account on a different machine.

Solution

After learning that a different login and machine would not solve my problem, I know I am now in serious troubles. It doesn't make much sense that the conflict resolution is recorded anywhere else outside of my computer without me check-in anything, but now it seems the only logical way to think it is happening.

Instead of merging from projA to projB again, I now made a clone of projB by branch out projB to projB-Clone.

I then merge from projA to projB-Clone and I am now getting my Resolve Conflicts screen with x number of conflicts pending my action. After resolving my conflicts, I now need to commit my changes to projB-Clone.

In our projB-Clone, we have all the merged code from projA after the previous merge, we are now ready to merge this changes to projB. As anticipated, there should not be any conflicts, we are literally just copying / replacing files from projB-Clone to projB.

Finally I will merge projA to projB once more to check if they are identical and no conflicts. From this point, we have completed our original attempt of merging projA to projB and it is now safe to delete projB-Clone.

Merge from projA to projB via projB-Clone

Thoughts

It is an unresolved mystery why TFS records conflict results on the server where there were no check-ins or commits. I never had similar issues in other file repository like SVN. The 4 way operations to work around an undo resolve conflicts button? Certainly not appreciated.