probably- I think I have sorted it - it was due to transferring files from laptop to iMac
EEP THAT OLD iMac!!
Mine died and I got a 2019 version- nowt wrong with it EXCEPT I can no longer use Ps CS6 which worked perfectly well and didn't require a sub
I wouldn't bother upgrading- not yet anyway - I can't tell any difference in real world editing between my 2013 iMac and the latest one with the highest possible specs and twice the memory of the old one - SAVE your money mate!
K