XPS 8940, BIOS 2.22.0 won't install

What error did you get and how did you try to install it, via Windows or a USB drive?

@ispalten​ Via Windows. No error message. When I click on downloaded file to install, User account control page comes up: "do you want to allow this app to make changes to your device?" I click yes, and then nothing happens.

@gotlieb74​ Had no problem installing BIOS update 2.21.0,2.21.0 several weeks ago.

@gotlieb74​ 

I did it that way, via Windows, but I have UAC turned OFF. I 'think' I know what I'm doing and allowing a program to install. If I'm 'wrong', I've got a back-up to install the OS from.

I've not seen reports like yours though for any BIOS, and you didn't have it the last time.

Alternatively, use the USB flash drive root. Put the BIOS file (only file) on an flash drive, and keep it plugged in. Power off, power on, and use the F12 key to get the special F12 menu. Select the USB drive to boot from and it will install that way (as I recall how to do it, I hardly ever do that so I might have it wrong?). I think it is correct though.

@gotlieb74​ 

Possible you have a BAD incomplete D/L, and if the USB method fails, probably so... get it again and see if it gets fixed that way?

The bios update finally came up in windows updates and was able to install via that means. Previous download was from Dell support website.

I would suggest you enter BIOS and turn OFF Capsule Update.

You really don't want MS Update installing DRIVERS for you without your permission. It isn't only the BIOS that it can do.