Database compression

The databases will be compressed regularly. A backup is created, before the compression starts (<database_name>.bck).
The place where this backup will be saved can be set under the Database tab of Options in the Extra menu. This is by default the directory where the database file itself is situated.
If an error might occur with the compression, then you could use this backup by changing the file extension from '.bck' to '.mdb'. Then try to login again.

Compression is important for the integrity and speed of the database.

How often the database have to be compressed, depends on how much data is added or deleted each day. This will probably be much more for Bill Of Materials then for Product Information Center.
You can change the frequency of compression, by selecting Options in the Extra menu.

You can change this setting for each application

The database can only be compressed when there are no users logged in. And while compiling, the database is opened exclusively. This means that when the database will be compressed, no user can log in. When a user attempts to log in, the window Waiting for connection will be displayed. This window will automatically retry to connect after 15 seconds.