Archive Utility Error 13 - Permission Denied attempting to create archive
It is not a good idea to compress the folder as a zip. Time Machine uses directory hard links a lot and zip does not recognize them. So you might end up with a zip archive 10 time (or more, depending on size and modification frequency) bigger than the space your Time Machine backup originally requires. If you have to have your backup as a file, then create a compressed image from your Time Machine disk.
Open Disk Utility. Select your TM drive, and go to &quot;File - New Image - Image of &quot;. Then choose &quot;compressed&quot; in &quot;format&quot;. Choose a location and click &quot;save&quot;. This operation might take several hours to several days depending on the size and complexity of your backup.
If you want to do it no matter what, you have to use the command line.
sudo zip -9ry /where/you/want/zip/to/be.zip /path/to/backup/