Some of the worst issues in Outlook are the ones which keep it from launching properly. You usually get this because there’s something wrong with the PST backup file, and there are many ways to work around that. But some of the times when you cannot start Microsoft Outlook Invalid XML errors are the cause of the issue. If this is the case, you’ll get some kind of error message, with codes like 0x80042108, 0x80040119, and 0x80040600. To the average user this is no more understandable than Latin or Greek. And you’re probably one yourself, so copy the error code and look it up online to see what’s ailing your favorite email client.
Chances are you’ll get the type of issue from the code right away and probably also get a detailed fix for it. There are plenty of user handled forums dealing with this kind of thing, and these aren’t hard to find. You’ll probably have one of these in the top results for your Google search.
Assuming you’re using the 2007 version of Outlook, the error occurred when you tried launching the program. When the application fails to start and you get one of the errors just mentioned, you don’t know what to do. The only thing you can infer from the message itself is that there’s something wrong with the XML files.
Usually such an issue derives from the loss of an important file, a virus infection that’s acting up, or even something that went wrong with the installation of the software itself. Find out the cause, and then you can get started on solving the issue. A general fix could be tried instead, and if that works, then you need to go no further. This involves executing code in the command line to reset the Outlook navigation pane. Bring up the CMD window and type in Outlook.exe /resetnavpane, and then hit Enter.
If that didn’t do it for you, the next tack is deleting the old corrupted XML file so Outlook creates a new one in its place. This needs to be done before you run the application, so that the new file gets created at launch. It’s in this folder path: Documents and Settings\… \Application Data \Microsoft \Outlook.
As mentioned before, some of the times when you cannot start Microsoft Outlook Invalid XML errors are the cause of the issue. But this isn’t always the case, and when it is, you get an error message that’s pretty clear.