If the delete reservations and related settings are unavailable in DHCP Manager, you may notice that the DHCP service may fail to start and Jetpack.exe can't compress the database. You may have the following event:

Event ID 1010: The DHCP server encountered the following error when cleaning up the user database: The system cannot find the file specified.

The above behavior is sympomatic of having replaced the Dhcp.mdb with an earlier version or if the DHCP scope is corrupted.

If you have a backup copy of Dhcp.mdb:

1. If the DHCP service is running, Stop it.

2. Delete %SystemRoot%\System32\Dhcp\Dhcp.mdb.

3. Place the Backup in %SystemRoot%\System32\Dhcp\Backup\Jet\<New folder>.

4. MOVE the backup to %SystemRoot%\System32\Dhcp.

5. Start the DHCP service.

If a backup is not available:

1. Record the scope settings and reservations, if possible.

2. If the DHCP service is running, Stop it.

3. Delete %SystemRoot%\System32\Dhcp\Dhcp.mdb. You will loose your reservations and lease information, but some scope settings will be restored from the registry.

4. Start the DHCP service.

5. In DHCP Manager, double-click the DHCP server and click the correct scope.

6. On the Scope menu, click Active Leases and click Reconcile, followed by OK.

7. In Server Properties, set Conflict Detection to 4 or higher and press OK.

8. If you find any bad addreses in the lease database, delete the bad address entries and Reconcile the database.

9. On a client, type ipconfig / release, followed by ipconfig / renew.