I run my late 2015 iMac from a 500gb external SSD boot drive. Suddenly I have only 38GB spare storage despite thinking I had used about 220GB.
Disk Utility shows 445GB used as data. By summing all the storage shown by using ‘get info’ on folders I estimate 250GB. The mystery would seem to be the 217GB of ‘other’ as shown on System Information:
I can’t seem to account for this ‘other’ storage by adding up the space used by folders in finder. Before I get further to adding up the sizes of lots of folders, is this ‘other’ storage likely the problem? What could this ‘other’ be to be so much, in addition to the photos/document already listed above in the System Information?
I have emptied downloads folder and trash. Time Machine backup to another external drive ([EDIT: but which has been giving me problems lately and disconnecting]. Dropbox and OneDrive both installed, and included in my estimate of usage. [EDIT in response to post below: I also back up to Backblaze].
Where should I look next to resolve the issue?