If you get errors about data corruption when starting up MailStore Home, here's how you can fix it.
MailStore uses a Firebird Database for storage. Luckyily Firebird includes tools to repair databases. Lets get them here:
https://firebirdsql.org/en/server-packages/
Version 2.5 worked for me for Mailstore 11.2. On newer versions of MailStore you might want to try a later version.
This guide was perfect for the repair run
https://www.ibphoenix.com/resources/documents/how_to/doc_5
Notice: You'll need to add the switches to access and to restore the databases.
-u SYSDBA and -p masterkey
Before you start, backup your corrupted database MailStoreFileGroup.fdb.
This is what I ended up doing:
(1) Fix the errors
gfix.exe -m -f -i -user SYSDBA -password masterkey MailStoreFileGroup.fdb
(2) Backup the database
gbak -b -v -i -user SYSDBA -password masterkey MailStoreFileGroup.fdb backup.fbk
(3) Restore the database
gbak -create -v -user SYSDBA -password masterkey backup.fbk MailStoreFileGroup_reborn.fdb
Finally, replace the MailStoreFileGroup.fdb by MailStoreFileGroup_reborn.fdb