I had an issue the other week where after importing a custom management pack the System Center Data Access Service and the System Center Management Configuration services refused to stay started (they started and almost immediately stopped again).
The normal process to remove a management pack is to crack open PowerShell and use Remove-SCManagementPack
However, in this situation without those service started the powershell cmdlets just won't work.
So, after speaking to PSS, using SQL to remove them directly out of the DB was they way to go.
I would NOT say this is a supported method, ONLY ever do this under advisory of Microsoft and DO NOT blame me if it destroys your Service Manager infrastructure. This is in no way a replacement to having regular working backups.
1) Backup the ‘ServiceManager’ DB.
2) Find out the ManagementPackId of the loaded management packs by using the below SQL query:
select * from ManagementPack order by MPLastModified
3) Note the ID of the MP you need to remove.
4) Then execute the following –
exec p_ManagementPackRemove ‘<GUID of MP>’
5) Once it’s done, try to restart the Service Manager related services (Data Access and Management Configuration).
6) If it starts successfully, try staring the console.