Because it is a split archive, you cannot open it by itself; it requires all subsequent parts (e.g., .002 , .003 , etc.) to be present in the same location to successfully extract the full contents. How to Open It To extract the files, follow these steps:
The file _AAA_STALKER2__2.7z.001 is the . It likely contains a portion of data for a file related to the game S.T.A.L.K.E.R. 2: Heart of Chornobyl . _AAA_STALKER2__2.7z.001