Because files on volumes formatted with the version of NTFS included with Windows 2000 can be read and written to by Windows NT 4.0 Service Pack 4 or later, Windows 2000 might need to perform cleanup operations to ensure the consistency of the data structures of a volume after it was mounted on a computer that is running Windows NT. Features affected by cleanup operations are as follows.
Disk quotas If disk quotas are turned off, Windows 2000 performs no cleanup operations. If disk quotas are turned on, Windows 2000 automatically cleans up the quota information by rebuilding the index.
If a user exceeds the disk quota while the NTFS volume is mounted by a Windows NT 4.0 Service Pack 4 or later system, and disk quotas are strictly enforced, all further disk allocations of data by that user using Windows 2000 fail. The user can still read and write data to any existing file, but cannot increase the size of a file; the user can delete and shrink files. When the user is below the assigned disk quota, disk allocations of data can resume. The same behavior occurs when a system is upgraded from Windows NT to Windows 2000 with quotas enforced.
Reparse points Because files that have reparse points cannot be accessed by computers that are running Windows NT 4.0 or earlier, no cleanup operations are necessary.
Encryption Because encrypted files cannot be accessed by computers that are running Windows NT 4.0 or earlier, no cleanup operations are necessary.
Sparse files Because sparse files cannot be accessed by computers that are running Windows NT 4.0 or earlier, no cleanup operations are necessary.
Object identifiers Windows 2000 maintains two references to the object identifier; one on the file; and one in the volume-wide object identifier index. If you delete a file that has an object identifier, Windows 2000 must scan and clean up the entry in the index.
Change journal Computers that are running Windows NT 4.0 or earlier do not log file changes in the change journal. When Windows 2000 starts, the change journals on volumes accessed by Windows NT are reset to indicate that the journal history is incomplete. Applications that use the change journal must be able to accept incomplete journals.