Can two users use a single file simultaneously
Technically, there is nothing which will stop two users using the same file simultaneously in Microsoft Money. However, it is not a recommended or supported configuration and I would firmly advise that you don't do it.
Microsoft Money is written and designed as a single user product. Using it on a multi-user machine and accessing a file at the same time (for example through different sessions in terminal server) is asking for trouble. Although you may be lucky, the luck might not hold out and a corrupted file would be the expected result.
Although a lock file (.lrd file - see
FAQ Article 196 for more MS Money file extensions) is created when you use Microsoft Money, this is not an exclusive lock. Microsoft Money data needs to be accessible and changed by certain programs (eg Microsoft Money for the Pocket PC, and background online bank updating).
If you need a program which can allow simultaneous access, this is probably not the personal finance program you want.
FAQ Article 67 has a comment from a MSN Money team member on simultaneous network access to Microsoft Money files, and why it's not recommended.