I created a 20gb encrypted folder on my main system drive for a special project and now want to delete the folder and recover the 20gb back to the system drive. I know you can drag the .dmg to the trash but will that recover the space and add it back to the main system drive? If not how can I recover the space? Thanks.
If the Mac is using the APFS file system (macOS 10.13+), then sometimes the space won't be recovered right away due to macOS utilizing APFS snapshots for backups which may retain the data you deleted. Once the backups have been transferred to the backup drive, then the snapshot should be deleted which will then free up the space.
View APFS snapshots in Disk Utility on Mac - Apple Support
https://eshop.macsales.com/blog/56681-working-with-macos-snapshots/
Also, if you copied those items to another location on the same APFS volume, then the data is actually only stored once with two links to it. Deleting just one of those "instances" will only delete the one link, which leaves the actual data behind since there is still one link to the data remaining.
https://www.maketecheasier.com/apple-file-system-better-than-hfs/
Things are more complex these days.
If the Mac is using the APFS file system (macOS 10.13+), then sometimes the space won't be recovered right away due to macOS utilizing APFS snapshots for backups which may retain the data you deleted. Once the backups have been transferred to the backup drive, then the snapshot should be deleted which will then free up the space.
View APFS snapshots in Disk Utility on Mac - Apple Support
https://eshop.macsales.com/blog/56681-working-with-macos-snapshots/
Also, if you copied those items to another location on the same APFS volume, then the data is actually only stored once with two links to it. Deleting just one of those "instances" will only delete the one link, which leaves the actual data behind since there is still one link to the data remaining.
https://www.maketecheasier.com/apple-file-system-better-than-hfs/
Things are more complex these days.
A Folder being Removed and put to Trash is half way there.
Empty the Trash will finish the job.
The Space should become available as Empty Space.
One can do Rebuild the Spotlight index on your Mac just to be more assured.
Deleting an encrypted folder
