Incompatible database version

It happened to me several times by now that I get error messages related to an incompatible database version. Examples of error messages are:

Error: Incorrect or incompatible database version. If you have applied any patches or hotfixes for Microsoft CRM, please apply them to this server as well.-2147467259 (0x80004005) Description: Unspecified Error.

and

The version of cdf database you are attempting to use does not match the version of your microsoft crm database.

These errors might prevent you from installing hotfixes, running the Data Migration Framework tools or even prevent the security service to start up. In this case there is something wrong with the version number of the database. This number is stored on several locations. All of these should be the same. The locations this number is stored are:

- CRM Database: "[clientname]_METABASE" Table "BuildVersion"
- CRM Database: "[clientname]_MSCRM" Table "BuildVersion"
- CRM Database: "cdf_mscrm" Table "cdf_BuildVersion"
- Registery key: HKLM SOFTWARE Microsoft MSCRM CRM_Server_Version
- Registery key: HKLM SOFTWARE Microsoft MSCRM Database Version
- Version of file c:\program files\microsoft crm\server\bin\crmsecurityservice.exe.

The error should be gone when you modify these to reflect all the same number. Before making any modifications to any of these settings, you should ofcourse make sure that you do have backups.