Close and restart your computer. Often this is all you need to do.
Please perform File Maintenance. File Maintenance will repair index errors, correct common record problems, remove references to unused information, and compact the family file. Here are the steps:
Click on File > File Maintenance.
Choose the Check/Repair option.
If any error messages popup during the repair steps, click No in the message box, which will alow to repairs to continue.
If errors are found, re-run Check/Repair one more time to make sure that all problems are fixed.
If that does not solve the problem, export all your records into a new Legacy family file (File > Export To > Legacy file) and use the new file.
If the problem still occurs one user has reported that when they uninstalled MS Office from their computer and re-installed Legacy the problem went away. Try uninstalling MS Office from your computer.