I've tried strict, I've tried loose, I've tried 777 with owner www-data.... same issue.

I'm setting these permissions on the ENTIRE root folder of backdrop cms.... not just the /files directory... with same results.

 

 

Accepted answer

Ok, this is nuts... on the root folder:

chown -R www-data.www-data .

and

chmode -R 775 *

 

and that fixed it.  Which I'm 99.99% sure I tried before already.

Comments

Reset those permissions to normal (don't recommend 777 on a live site), and next try looking at the file system settings. Maybe the site can't write to the specified temp directory?

admin/config/media/file-system

so, where exactly would "admin/config/media/file-system" be on a Ubuntu install?

 

And... No, I wouldn't set those permissions on a live site either, it was my attempt to get it working, at all.

Ok, this is nuts... on the root folder:

chown -R www-data.www-data .

and

chmode -R 775 *

 

and that fixed it.  Which I'm 99.99% sure I tried before already.

Glad that worked and sorry it was so difficult. File permissions and ownership still baffle me at times.