Simply going through the causes and fixes won’t help until you have a little knowledge about what this error code is all about. So, here is a quick view about this error code 12045. This error can be experienced when you try to update the QuickBooks desktop or download the latest release for the same. In a couple of scenarios, the error messages aren’t noticeable, but at times you might experience a warning message such as in the case of 12045 error. It shows up on the screen stating: Error 12045: Failed to download the update. Other than this, there can be a few more errors that can be seen when updating the QuickBooks software; it includes QuickBooks error 12157, 12038, 12037, 15xxx errors, etc. There are a few factors that might trigger such errors in QuickBooks. Let us discuss further the causes.