Computers or networks can occasionally fail. In turn this can lead to your data file becoming corrupted. If VT Transaction+ exhibits unusual behaviour, choose the File>Maintenance>Check For Errors/Repair command. This checks the file for inconsistencies and errors. For instance, a stored account balance may not match the sum of the entries in the account. If any error is found, you will be prompted to automatically repair the file. Sometimes, the repair process has to remove a small number of corrupted transactions. In this case it will report this, usually with the transaction reference numbers. On exceptionally rare occasions a large amount of data may be lost. This illustrates the importance of keeping back up copies of your data files.