Some antivirus programs (NOD32, …) cause problems with the Flexi database system. These typically manifest as Flexi becoming unresponsive in the middle of work.
The settings change must be made on the local installation or network server (i.e., where the data is stored).
The antivirus must be configured to exclude the Flexi data directory from scanning — usually C:\winstrom-data.
A technical description of the issue in English can be found on the database server website.