The Business Database is not valid

4

@Ali_Senger, your problem occurred because your backup was made by a version of Manager so old the switch to SQLite structure had not yet occurred. For a long while, conversion was part of the installation script. But that ceased after v20.9.89. So you will need to upgrade in two stages: first to 20.9.89 (downloaded from Github), then to a more current version. See this topic for information and links: Opening old files in new version - #10 by Patch.