emclient has an error, afile or ... is damaged or unreadable

eM Client (5.0.18025.0)
Windows: Microsoft Windows NT 6.2.9200.0, Framework: 2.0.50727.6400
The following error has occurred:
System.IO.IOException: Bestand of map is beschadigd en onleesbaar.

bij System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
bij System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy)
bij System.IO.FileStream…ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options)
bij MailClient.Program.Main(String[] args)

i can’t open emclientenymore after taking the free version

It seems that your database is corrupted. The easiest way to resolve this issue is to restore your data from a backup.