When you attempt to log on to your Exchange 2000 Server, you receive a BSOD similar to:

<b>STOP 0x0000001E (0xc0000005,0x8051aebb,0x00000000,0x6f007e0f)

KMODE EXCEPTION NOT HANDLED NTOSKRNL.EXE 80518ebb80400000 384d5876-ntoskrnl.exe</b>

If you look at the memory dump file, you see a callstack that is similar to the following:

<b>bfcaba0c 8051aebb e1013008 ffffffff e1013008 ntkrnlmp!HvpGetCellPaged+0x35
bfcaba24 8051df08 e1013008 0021a300 e11020f4 ntkrnlmp!CmpFreeSecurityDescriptor+0x19
bfcaba40 8051e0ee e1013008 0021a300 e1232304 ntkrnlmp!CmpFreeKeyValues+0x66
bfcaba68 8051db09 e1013008 000ea0f0 e11020f4 ntkrnlmp!CmpSyncKeyValues+0x22
bfcabab4 8051d956 e24ba000 00000400 00000002 ntkrnlmp!CmpCopySyncTree2+0x1a3
bfcabae0 80511c1c e1013008 000001e0 e1013008 ntkrnlmp!CmpCopySyncTree+0x44
bfcabc44 8050e882 00010002 8050e82e 81f59508 ntkrnlmp!CmpSaveBootControlSet+0x1a8
bfcabc90 804624e9 00000004 00000000 e24b5fc8 ntkrnlmp!NtInitializeRegistry+0x54
bfcabc90 8042f863 00000004 00000000 e24b5fc8 ntkrnlmp!KiSystemService+0xc9
bfcabd0c 8050e84e 00000004 8050e82e 000a001f ntkrnlmp!ZwInitializeRegistry+0xb
bfcabd58 804624e9 00000004 00000000 00000000 ntkrnlmp!NtInitializeRegistry+0x20
bfcabd58 77f9a2e4 00000004 00000000 00000000 ntkrnlmp!KiSystemService+0xc9
0065fa2c 01004605 00000004 0065fa94 01016230 ntdll!ZwInitializeRegistry+0xb
0065fa70 010044e3 0065fabc 6e4f6373 0065faa8 services!ScAcceptTheBoot+0xca
0065fa90 77d8626c 00000000 00000001 02020202 services!RNotifyBootConfigStatus+0x7e
0065faac 77da3bca 0100447d 0065fac0 00000002 RPCRT4!NdrServerMarshall+0x12fa
0065fd10 77da3589 00000000 00000000 0065fdfc RPCRT4+0x63bca
0065fd2c 77d634a2 0065fdfc 0008e380 0065fdfc RPCRT4!NdrServerCall2+0x17
0065fd64 77d500de 010065fd 0065fdfc 0065fe40 RPCRT4!I_RpcBindingInqDynamicEndpointA+0x3044
0065fdbc 77d4ffb2 00000009 00000000 0065fe40 RPCRT4!I_RpcMapWin32Status+0x39f
0065fddc 77d56227 0065fdfc 00000000 0065fe40 RPCRT4!I_RpcMapWin32Status+0x273
0065fe44 77d56420 00000000 00116448 0010e4d0 RPCRT4!I_RpcTransDatagramFree+0x19f9
0065fe58 77d55db1 00000000 00000009 00000001 RPCRT4!I_RpcTransDatagramFree+0x1bf2
0065fe90 77d55671 00116430 00000003 00000009 RPCRT4!I_RpcTransDatagramFree+0x1583
0010e4d0 89abcdef 00000040 00000002 00000000 RPCRT4!I_RpcTransDatagramFree+0xe43
77d42078 77d55061 77d56876 77d5502c 77d54fc0 +0x89abcdef
77d491a9 c2042444 08c20004 74c98500 6a018b07 RPCRT4!I_RpcTransDatagramFree+0x833
2308418b 00000000 00000000 00000000 00000000 +0xc2042444</b>
These occurrences are indicative of a damaged registry key in the Last Known Good control set. When the system tries to prepare to copy the current control set, it fails to clean up the Last Known Good control set.

If you can access the Exchange 2000 Server computer remotely:

1. While the Exchange 2000 Server computer is paused at the logon screen, remotely connect to its' registry by using Regedit. On the Registry menu, press Connect Network Registry, type the computer name of the Windows 2000 Exchange Server, and press OK.

2. Navigate to that computers HKEY_LOCAL_MACHINE\System\Select key.

3. Record the data value of the LastKnownGood Value Name.

4. Change the data value of the Failed Value Name to the data value of the LastKnownGood Value Name from step 3.

5. Record the data value of the Current Value Name.

6. Change the data value of the LastKnownGood Value Name to one greater than the data value of the Current Value Name from step 5. If the data value from step 5 is 2, set the data value of the LastKnownGood Value Name to 3.

7. Exit Regedit.

8. Restart the Exchange 2000 Server computer.

9. Logon to the Exchange 2000 Server computer.

If you can NOT access the Exchange 2000 Server computer remotely:

1. Install a parallel copy of Windows 2000 to a different partition on the Exchange 2000 Server computer.

2. Use the technique in tip 182 and Regedt32 to load the System hive of the Exchange 2000 Server install, calling it ExW2KSys.

3. Navigate to HKEY_LOCAL_MACHINE\ExW2KSys\Select.

4. Perform steps 3 through 6 of the remote access procedure.

5. Select the ExW2KSys key and press Unload Hive on the Registry menu.

6. Exit Regedt32.

7. Restart the Exchange 2000 Server computer.

8. Select the Exchange 2000 Server installation.

9. Logon to the Exchange 2000 Server computer.