I found 2 which produce this issue. 1. many save games Reduce your save games to one, your latest, save game. It will maybe not so fast as a totally fresh save game, but much better! 2. Defect HDD How to check the HDD (Win Vista, Win7, Win10) - press start button and use the search function (or direct Cortana) and enter CMD - click with right mouse button on CMD and choose 'start as admin' (do not know the exact wording in english!) - write chkdsk /r/b if your game is on c: and press enter - you will be asked if you want to check the HDD during the next start of windows, answer (y)es. - restart pc, do not stop the disk checking, wait, wait, ... and wait - after windows started again, press start button - enter CMD in the command line - click with right mouse button on CMD and choose 'start as admin' (do not know the exact wording in english!) - write chkdsk if your game is on c: and press enter (yes, without /r/b) at the end it shows if there defect parts (for example '8 kb in defect sectors', do not know the exact wording in english!) If your game is on d:, write d: and press enter in the CMD application before starting the CHKDSK /r/b. Same with e: or f: and so on... (maybe chkdsk works on the other drives automatically, you need only accept that the HDD is not usable during testing!) I know it is possible to start CMD also in the properties of the drives, but win 10 didn't let me choose the /r/b options which I could doi in earlier OS's. In older windows it is also possible to to the same steps. Only the command line is not available and you need to press on 'run' after the start button (again I'm not sure if the name of it is really 'run', I'm seldom working with WinXP) If you find no error, but you have on the same HDD, you have Fallout installed, different partitions, check also the other partitions. Other step would be to read the SMART data from you HDD's. You will find several applications for this with google. For example: CrystalDiskInfo Testing the HDD is interesting if you OS is slow for example, too. Big HDD's need much time, do it over night!