Occasionally, a power outage, a premature shutdown of the machine, or a machine crash can lead to data corruption in a database application. Unfortunately, the 4D Business Kit application is not immune to these and other factors that can cause data corruption.
If your 4D Business Kit application is corrupted, have 4D Tools scan and attempt to fix the corruption. Just drag and drop the data file (ending in .4DD) onto 4D Tools. You can download 4D Tools from: https://www.4d.com/products/downloads_4d.html. Check the documentation on how to use 4D Tools if you don't know or have never used it before. The username to open the 4D Tools on the default data file is "repair." No password is needed to open the data file.