When you install the vCenter Server on a system in your own language (german for example) you might run into an issue that even after forcing the vSphere Client to english all error messages and e-mail notifications appers in german language. Having non-english error messages is a pain, if you try to google for solutions. If you work for an international company it also may be important that error messages are in english.
There is no official supported solution for this problem, but you can use this little workaround. This works with vSphere 4, 4.1 and 5:
- Connect to the Server where vCenter Server is running (RDP Client or Console)
- The language files are located in: C:\Program Files\VMware\Infrastructure\VirtualCenter Server\locale\
- Rename the de folder (or your language) to DE.old
- Copy the en folder to the same directory and rename it to de
- Restart vCenter Server Service
All error messages and alarm emails should now appear in english language.