The FDC reports that MQ is unable to access somthing (In this case, arith1 == 5 == access denied). The function doing this is trying to update a particular registry key which is outside the MQ tree and which is updated by the MQ installation.

1. It might potentially be caused if you have configured MQ so the user that the service runs under is not in the local mqm group, although that would not be a good thing, so you might want to fix that. To fix that, you would bring up an elevated (ie use the "run as administrator", not just one where you are logged in as an administrator) command prompt and issue

net localgroup mqm /ADD

Once you have done this, you might need to reboot the machine for it to be effective. Try restarting the service manually once, and if it doesnt help, try the reboot.

2. I've also seen this problem after a windows update which reset the registry permissions on a key which the MQ installation has previously updated, preventing it being updated when the queue manager starts.

When this occurs, depending on the version of MQ you might also get an error message in the global errors log (and possibly the event log) saying:

AMQ6509E: Unable to update registry value.

EXPLANATION: An attempt was made to update the value of 'WebSphere MQ QMgr (myqm)' in registry key 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC\XADLL' to 'C:\mqinstalls\MQ9120\bin64\amqmtsxatm.dll', however a problem was encountered when doing so. The system return code was 5. ACTION: Verify that the permissions on registry key 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC\XADLL' allow the executing user to modify values within it. Executing 'crtmqdir -f -a' under a local computer administrator user account will restore any missing permissions required by MQ.

You need to follow the instructions in the error message, ie To fix that, bring up an elevated (ie use the "run as administrator", not just one where you are logged in as an administrator) command prompt and issue

{path to MQ installation}\bin64\crtmqdir -f -a

If your version of MQ does not have such a binary, manually browse in regedit to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC\XADLL and right mouse button on XADLL->permissions and give mqm rights to query and set values for that key.