DropBox has a nice feature called “Smart Sync”, which deletes selected files from your local disk, while preserving the file on the cloud. It shows fake placeholders instead of files, and downloads them only when you need.
I have used that feature on various large files; but despite that, Time Machine kept telling me that there is not enough space on my backup drive.
Solution: Go to dropbox.com – settings, and activate “Smart Sync update for Mac”.
Then, let DropBox breathe & arrange your files. When DropBox has completed the update; reset your Time Machine backup disk and backup from the scratch.
If I understand correctly;
- Deactivating this option makes your Mac think that those large files are really on your drive, and confuses Time Machine.
- Activating this option makes your Mac see the files as they really are (zero bytes), and Time Machine can operate as intended.
A similar approach can also solve DropBox performance problems on the Mac.