Jobs or customers are missing after reopening

Steps

Check the demo banner and choose Exit demo if needed.
Clear the search field and set the record filter to All. Check Archived jobs as well.
Confirm you are signed into the same Windows account and using the same computer as before. Each Windows user's application-data folder is separate.
Open Help & troubleshooting and run Check this workspace. The report identifies demo versus company mode and checks database consistency without changing records.
If data really is missing, preserve the current files. Review an automatic recovery copy or your own backup before choosing Restore a backup.

The expected saved records return after correcting the workspace or filter, or after a reviewed restore.

If records disappeared after a reported successful save on the same account, report it as a product issue. Do not delete the existing database.