The problem is not the missing file of 'ISDone.dll or Unarc.dll' file, as many claim. This message comes for several reasons. 1- The antivirus program stops the file from being installed (if you have an antivirus program other than Windows, just go to its settings and disable it) 2- Downloaded files are corrupt or missing 3- Because of your RAM capacity There are two other reasons that are not common The reason is that if you do not pay attention and install the game or program on a disk or SSD with insufficient space, this message will appear to you. The other reason, which is rare, is that if your HDD is very old and makes a lot of noise, it may cause this problem. Thank you for watching the video. Please support the channel by subscribing and liking ------------------------------------------------------------------------------------------------------------------------------------------------------------------- How ho fix ISDone.dll How to fix Unarc.dll