Interactive rebase operations frequently fail with this message:

error: There was a problem with the editor ''C:\Program Files (x86)\Atlassian\SourceTree\tools\stree_gri''

Full output log:

git -c diff.mnemonicprefix=false -c core.quotepath=false -c "sequence.editor='C:\Program Files (x86)\Atlassian\SourceTree\tools\stree_gri'" -c "core.editor='C:\Program Files (x86)\Atlassian\SourceTree\tools\stree_gri'" rebase --continue
error: There was a problem with the editor ''C:\Program Files (x86)\Atlassian\SourceTree\tools\stree_gri''.
Please supply the message using either -m or -F option.

Could not commit staged changes.

Completed with errors, see above.