Merging from master to feature branch. One file has been deleted on master, but is modified on the branch's HEAD. Notification is given in detailed merge feedback. In the Log/History view, the file in question is marked with an orange exclamation mark in staged and unstaged areas.

Right-clicking and selecting "Resolve conflicts -> Launch external merge tool" (I am using Beyond Compare, but not sure that is significant) results in the following:

• The four helper files are created; BACKUP, BASE, LOCAL, REMOTE. The latter is empty.
• The merge information dialog pops up, stating that you need to QUIT the merge tool to complete the merge process

... and that's all.

No merge tool is launched, and no other message appears.

I assume this may have something to do with the empty REMOTE revision.

To resolve it, I had to clean up by first aborting the ST merge dialog and removing the helper files in unstaged, and then notice that the file in question was gone on the incoming changes. Finally, I "merged" it by Removing (Ctrl-Del) it from unstaged, which supposedly recreated the situation on the other branch, and correctly ended up with a."deleted" mark on the staged file.