Hello there, Mary53.
Error 15420 occurs when QuickBooks Desktop (QBDT) encounters issues while trying to update the program, download payroll or tax updates, or due to interference from your firewall/antivirus. Here’s how you can resolve it:
- Ensure QuickBooks Desktop is updated.
- Download the latest payroll tax table update for QBDT.
- Run QBDT as administrator.
- Check and adjust firewall or antivirus settings.
If you have any questions or need additional assistance, the Community is always here to help.
