Outlook cannot open

[Barry7]

after installed VMware 16 Player, Outlook 2016 failed to open

[scott28tt]

Version of Player?

Host OS version?

You literally installed Player and Outlook stopped working?

Errors? Rebooted? Repaired Office? Removed Player?

[Barry7]

Version of Player? 16

Host OS version? Windows 10

You literally installed Player and Outlook stopped working? Yes

Errors? Rebooted? Yes Repaired Office? Yes Removed Player? Yes and then Outlook could open

[scott28tt]

You missed one.

Errors?

[Barry7]

error: cannot start MS Outlook. Cannot open the Outlook window. The setof folders cannot be opened. The file....is not an Outlook data file (.ost).

[RaSystemlord]

Are you sure that you didn't have a Windows Feature Upgrade in between?

I'm asking because this is a typical problem that happens when Feature Upgrade renders some applications to a non-working state. With Outlook, this happened with the very first releases of Windows 10.

The solution, installing the application again, in this case Outlook, is the solution that makes the application to work. (This has to do with Windows Feature Upgrade moving everything to "windows.old" folder and then it doesn't always copy all the relevant parts of all the software to the new "windows" folder.) So, in this scenario, removing VMware was not necessary at all.

Of course, this could be incompatibility between .dll's (or similar) with Outlook and VMware. In that case, I'm sure you will get advice directly from VMware.

[Barry7]

thanks @RaSystemlord for your analysis, we upgraded Vmware Player to version 6 and then update Windows 10 to version 21H1 (latest) and come out the Outlook issue.

From your solution, so we reinstall the MS Office 2016 suit (include Outlook) could fix the issue? I already tried to reinstall the Vmware Player but the Outlook issue come back after several hours as per user report.

[RaSystemlord]

@Barry7 

Yes, if this was indeed because of Windows Feature Update (which you did run), installing the application again, solves the issue.

I have had some applications, which were corrupted EVERY time, when a CERTAIN Feature Update was done. If I remember right, this was between versions 18.03 and 18.09. But this is application-specific and this is Feature Update -specific when this happens. Your case could be very well a similar event.

This is a rather intimidating problem if the reinstall takes lots of time. In my case, referred to above, I had to uninstall before a new install - but that is application specific and depends on what its install program is capable of. With MS Office 2016, not sure how it works, but I would try to run Repair first ... or then only the Outlook part of the uninstall/install if it lets to select installable modules (I know that some of the Office versions, don't let select anything by default when you first install them, not sure what you have there) or if that doesn't work, only Outlook+common parts ... and finally the whole bunch if nothing else works. I'm of course anticipating, based on your writing, that you might need to do this several times in your office and saving time might be very much desired.

[Barry7]

@RaSystemlord I just followed your advise and reinstall the MS Office completely but the same Outlook error come out after. Only until I removed the VMware Player, the Outlook come back normal. Please help or advise.

[RaSystemlord]

This is a bit strange, providing that you didn't do a reboot in the process, which very well can change things?

It is not self-evident that uninstalling any application can fix the system. It is possible, but only cases - that I can think of - which would allow this to happen would be:

- VMware uninstall restores old .dll's (or similar system files, I refer them only with .dll in the following). This is rather uncommon to happen, especially without any user interaction

- VMware installs a competing .dll that is used also by Outlook when VMware is installed. Dealing with such an issue, would require to inspect the system and first find the .dll in question. Then you would need to figure out what to do about it. In principle, either application has a mistake in their way of handling .dll's or their contents ... this should not happen

- so that this wouldn't be that easy to study, you would need to pay attention to conventional .dll's and .Net .dll's which don't work the same way (fixed registering or auto-registering)

- however, when this still happens, the most obvious reason for this is that, now that you have the new Windows 10 version in play, is either version NOT compatible with that Windows version? That would explain non-working dll's being installed and referred in the system. In principle, a new .dll should always work as well as the old one ... that is not true if the applications are not compatible with the overall architecture (the other explanation involves either software provider making a very big mistake by installing a non-compatible .dll with the same name)

Just as a guess: VMware registers a .dll that is not compatible with Outlook. When you uninstall VMware, it deletes the registry entry and then Outlook can use some other .dll. Solution: Don't know, but perhaps update either software to a newer version, which is compatible or better compatible with your Windows version.