reason: because some programs installed on disk D are in use, they cannot be formatted.

method: formatting in safe mode is the most convenient method. (Press F8 to select the safe mode)

Also correct an error: the "more than 3 g" you mentioned refers to the space on the hard disk, not the memory.

also, after formatting drive d, some programs (for example, many people will install QQ on drive d) will be unusable and need to be reinstalled.