18.04 LTS upgrade Monitors flashing

[uaebuntu]

I upgraded my Dell Precision Workstation from 16.04 LTS to 18.04 LTS, it has an nVidia P4000 quadro GPU, was running the nVidia drivers

After the upgrade only one screen of the dual monitors was working, the resolution of the working monitor was very low.

once the login was done the screen started flashing on and off and is virtually unusable.

The old unity "display" icon is gone so I can't even try and adjust the resolution.

I really need to fix this, but it seems I have two choices, clean reinstall of 18.04 or recovery of the 16.04 system. The former may not fix the problem and the latter seems defeatist, is there anything that can be done quickly (i.e between flashes on and off to try and fix this before cutting an 18.04 USB?

[Autodave]

Probably not.....assuming that you cannot do much between flashes. I have always found that a clean install is the way to go. Download your install file, burn it ti a disk or USB as an .iso file and boot from it. When you get to the screen that asks whether you want to try or install it, choose TRY. From there you should be able to now access the HD and then copy any files that you need to an external source before installing.

Once in stalled, make sure to go to settings and then additional drivers and let it find the Nvidia driver needed for you card. (It will be driver 390.xx.)

[uaebuntu]

Thanks

I cut a new USB, but didn't need to use it in the end :P

I used your advice to go to the software settings - additional drivers between flashes (laborious but better than new install!)

Selected the drivers and rebooted, both monitors up, no flashing

Was now able to us the nVidia tools to set the position and resolution of the displays. Will do clean installs in future!