I am suddenly having problems with my ChemFinder database.
Your database or a part of it could be damaged. If you can at least open your database in ChemFinder, you can export it and then import it to create a fresh database. To do so, open your file in ChemFinder. From the File menu, choose Export -> SD File. Give the .sdf file a name and note where you are saving this file. Make sure you save it to a different location than your original database or at least give it a different name. Once you have created the file, close the opened database, and choose Import -> SD File from the File menu. Browse to the .sdf file you just created and open it. This will create a new database. Note that data in subforms will not be exported.