You can control whether AutoCAD goes to the same folder all the time for "look in" or "save as", or whether it remembers where you went the last time you needed a block or an xref. The variable that controls this is REMEMBERFOLDERS. Set it to "0", and AutoCAD uses the "start in" path (from the shorcut's Properties). Set it to "1", and the last used path for each dialog box is saved. This applies across all drawing sessions.