Hi Ed_P,
Thanks for looking into my issue.
Exactly, it looks like the pictures have been saved on the flash drive as the memory usage went up significantly.
I am running MacOS High Sierra 10.13.5.
I view the pictures with standard Apple ‘Preview’ program.
I formatted the flash drive using these instructions: https://kb.sandisk.com/app/answers/detail/a_id/203
I am not getting any error messsages when I try opening pictures. Once I double click on the picture it shows a thinking wheel for 1- 2 seconds and then it dissapears and nothing happens. The thinking wheel is not a typical rainbow colour Mac wheel but the greyish one.
I have recently installed malwarebytes app.
Should I try removing malwarebytes app?
