I am running Ubuntu 16.04. I am getting a system problem detected pop up from apport which prevents display of my desktop and consequently prevents me getting to var/crash and getting rid of the popup. It has effectively paralysed my system, blank background spalsh screen, mouse doesn't work etc.

I've used an ubuntu live cd to go into the file system to check var/crash and it is clear it is a problem with the virtualbox kernel (I've been running windows under virtualbox successfully for several months but clearly I've messed up a recent setting). However the live cd will not let me remove the crash file so that I can login and deal with the virtualbox problem as the live user is not the owner of the original files and cannot change permissions to delete them.

I'm not that experienced so need advice on how I can get access to the filesystem to delete the appropriate file. I'm unwilling to do a complete reinstall as i had the ubuntu system setup pretty much as I wanted it.

I'd appreciate any advice, thanks in advance

Have you tried booting into recovery mode? Instructions are here: https://wiki.ubuntu.com/RecoveryMode

From the liveCD, simply "sudo su -" from a terminal (no quotes). Then you'll be root, and can remove the offending file(s).

Edit: works from Mint, haven't tried Ubuntu in years but worth a try.

Dear Frankbell and syg00

Many thanks for your helpful replies. Apologies for my delay I only get to work on my linux ssytem at the weekend.

syg00 the sudo su did not work for ubuntu. Bit liekt eh live cd I could see files but couldn't do anything to them as I had no privileges.

Frankbell. The boot to recovery mode worked. it took ages and loads of tries to get the timing of the shift press right but once one has done once it it is easy to spot when to actually press for future attempts

Following the revory mode instructions in teh link I was able to access files , delete the offend crash file and correct the system.

problem solved

many thanks

Alan