QuickBooks error code H505 is a common error that users often encounter. This usually occurs when a user tries to run his QuickBooks Desktop in multi-user mode. This error is part of the H error series and is related to error issues that occur when a user attempts to access a company file that does not exist on their device or network. To fix QuickBooks error H505, we have put together this article that explains this error in detail. We will explain the symptoms, causes, and solutions for this error.