Full Disk Access
System Settings › Privacy & Security › Full Disk Access: turn CoreTend on. macOS may ask to reopen it.
Help in the greenhouse
Answers to the usual questions. For anything else, open an issue on GitHub — without personal paths.
A folder cannot be read
Without Full Disk Access, macOS keeps some folders closed. CoreTend says when a result is partial.
Getting a file back
Click Undo right after a clean, or open the Trash and choose Put Back.
An app will not move
Some apps belong to the system or to an administrator. CoreTend leaves them in place and says so; remove them in the Finder if you are sure.
Removing CoreTend
Quit it and move it to the Trash. Its local data live in ~/Library/Application Support/CoreTend-Reconstruction.
Reporting a problem
Open a GitHub issue with your macOS version and what you saw. Leave out personal file names and paths.