what does "unrecognizable database format error" mean?

[Anneline]

I have an Access backend on the server with multiple frontends (about 6) on
other client machines. The tables are successfully linked. Data has been
successfully entered through the frontends until today. An error message
pops up saying "unrecognizable database format" - showing the path to the
backend. None of the other frontends allow access anymore. What has
happened and how can this be repaired?

 

[Rick Brandt]

I have an Access backend on the server with multiple frontends (about
6) on other client machines. The tables are successfully linked.
Data has been successfully entered through the frontends until today.
An error message pops up saying "unrecognizable database format" -
showing the path to the backend. None of the other frontends allow
access anymore. What has happened and how can this be repaired?

The file could be corrupted or someone might have changed the version to a
newer version of Access. Both can produce that same error message.