Fsutil, allows you to to adjust the max size for the reserved zone. example: fsutil behavior set mftzone 4 The values range between 1 through 4, with each equally 12.5% of the volume. E.g. a setting of 4 = 50% of the volume. There are few reasons to extend this, and you are better off to pre-allocate the MFT expansion with Diskeeper's FragShield than rely on the just-in-time expansion of the MFT into the reserved zone (less overhead, and elimination of the possibility of the MFT becoming fragmented). Use Frashield when the MFT is getting full (Diskeeper will notify you) or prior to adding a large number of files onto the volume. We have customers who leverage this feature for corporate HQ servers that are designed to receive many small files uploaded from branch locations. If you're a gamer installing games