Copy and paste error

Hiya peeps. So, I record gameplay videos with OBS in .mkv format. And 99.9% of all my recordings have been without problems but in the past week I've had 2 recordings that have had the exact same issue. When I try to copy the .mkv file to the same drive (different folder) or to a different...

I copied the files, ".max" saves 3dsmax from an SSD hard drive to a SATA hard drive, and after copying, the files larger than 1GB, when I try to open them, seem to be corrupted. Files of the same ".max" type (3ds max files) in the same folder, smaller than 900MB are still usable.

Please help me i can't find a solution it's suicidal 😭 😭 note my desktop is running on windows 7(i don't use it much and it has not been updated since ages) I switched on my desktop after 5-6 months and found that my system was attacked by ransomware virus most of my files pictures documents...