When the installation process cannot copy required files, usually because the installation files are faulty or missing, QuickBooks Error 1336 occurs. This problem can stop QuickBooks from starting or working correctly and usually occurs during the installation or update process. If you're experiencing QuickBooks Error 1336, there are a few easy fixes you can attempt. To start, consider restarting your computer to fix any short-term issues. Use the QuickBooks Install Diagnostic Tool, which automatically finds and fixes QuickBooks installation problems, if that doesn't work. Choose Repair from the Programs and Features list in the Control Panel to try fixing your QuickBooks installation if the issue continues.