This is of interest to Windows users as well as the MacHeads among you.
When someone inserts a USB stick or memory card in a Mac it creates a lot of hidden files. Normally you wont see these unless you have enabled “Show Hidden Files” in Windows Explorer or Mac Finder and they don’t matter.
Unfortunately when a Mac user deletes files they do not get deleted – they get moved to a hidden folder called “.Trashes”. They are only deleted when the Mac user empties trash on their Mac. If the files are on a memory stick the stick has to be in the Mac when trash is emptied in order for the files to be deleted.
When a Mac user takes a memory card from a camera, copies off the files and deletes them on the card, then nine times out of ten they don’t think to also “empty trash” – quite sensible as they probably don’t also want to delete all of the saved deleted files in the trash can on their main hard drive – they can’t selectively empty trash because Apple has decided they wouldn’t want to do that.
So you then have a memory card which is full of deleted files – if you put it back in the camera, the camera can’t see them and so it can’t delete them – it just reports the card as full.
If you stick the card in a PC then most users (who don’t have show hidden files enabled) will simply see (for example) an 8GB card with apparently no files on it and zero space free.
This is not useful!
So Mac users – if you delete files on a memory stick or card, please remember to empty trash before you eject the card.
Windows users – if you get caught by this then you can temporarily show hidden files (in Win10Pro it is an option on the View ribbon in Explorer, on older versions you have to go to Explorer Menu View Options and find the check box) then you can delete all of the things that show up with a dot (.) in front of their name and recover your space.
If your camera or other device says there is no space on the card when you know that there should be then this is probably what has happened.
As a Mac user at home this has been annoying me for years – I think I have now found a way to place something on the memory card/stick which will prevent Apple from trashing it and I will try and bundle this up as a little utility for both Mac and PC (there may already be something out there but I can’t find it – if you have please send me a link and save me the bother of reinventing that particular type of wheel)
Hope this is useful