0. Make sure "TortoiseMerge" is selected as a merge tool.
1. Start doing a merge in SourceTree from another branch (Git is used).
2. Right click on conflicted file - Resolve Conflicts - Launch external merge tool
Bug: if a file path contains whitespaces, SourceTree uses incorrect escaping with quotation marks.
Example of command line used:
"c:\Program Files\TortoiseGit\bin\TortoiseGitMerge.exe" -"base:./mac/Disk/Disk/App Core/SomeFile.m.BASE.9944.m" -"mine:./mac/Disk/Disk/App Core/SomeFile.m.LOCAL.9944.m" -"theirs:./mac/Disk/Disk/App Core/SomeFile.m.REMOTE.9944.m" -"merged:mac/Disk/Disk/App Core/SomeFile.m"
Expected: TortoiseGitMerge launched successfully. Correct command line:
"c:\Program Files\TortoiseGit\bin\TortoiseGitMerge.exe" -base:"./mac/Disk/Disk/App Core/SomeFile.m.BASE.9944.m" -mine:"./mac/Disk/Disk/App Core/SomeFile.m.LOCAL.9944.m" -theirs:"./mac/Disk/Disk/App Core/SomeFile.m.REMOTE.9944.m" -merged:"mac/Disk/Disk/App Core/SomeFile.m"