Blank screen after plasma upgrade

[marco07]

My 15.10 has been working quite well. Just today I upgraded the KDE plasma from 5.4.x to 5.5.x. and rebooted the system. Now after Kubuntu logo I get a blank screen and no desktop at all. I can access the folders thru tty using Ctl+Alt+F1 and logging in. It might be caused by my nvidia display driver. I have googled and searched the forum to no avail. Please advise!!
Thanks!
P. S. the system is a Lenovo Thinkpad T540p with bothintel and nvidia graphic cards. Willy was using the nvidia card prior to upgrading.

[marco07]

I have a W520 and it has given similar problems.

Have you tried to run update again from that terminal?

Yes. It did not help. I also did some suggestions i foun by googling to no avail either.

Something easy to try is to get into the BIOS/UEFI setup and force either the Intel or NVidia driver, including disabling the option for the OS to see and switch Optimus.
It is also possible to uninstall the nVidia driver.

I did not want to mess around with my stock OS. I thought that there might be a work around or solution for this. I had in my mind that, If not resolved, I could purge the ppa installation.

dpkg -r nvidia
This should make the system revert to the Intel driver.

Since I could not find any solution, I did purge the ppa installation of Plasma 5.5.x and reverted back to my 5.4.3 which I had actually upgraded using the backports repo when it was announced a while back. I wonder why it did not workout well this time around for 5.5.x.
I am good now.
Thanks for your reply!