A while ago, we encountered this error when doing merges in TFS (non-GIT ones):
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Microsoft Visual Studio
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Source Control Merge Wizard
Merge encountered 1 error(s) and 0 warning(s).
First error/warning encountered:
Server was unable to process request. ---> Object reference not set to an instance of an object.
See output tool window for information on any other errors.
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OK Help
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In the end this was caused by an out of disk space on the volume containing the TFS datastore.
–jeroen





