The proposed solution here is to make the casing of the path provided to the hashing function for the mutex consistent with something like:
By adding ToLower to UniquePath.
Run something similar to this from a batch file:
Note how the case of the drive letter is different. *D:* and *d:*. Any case-sensitive difference of the path will cause this problem, but the correctness of the drive letter can be the most undefined. One of the builds will probably fail with:
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-105027 in the post.