Not hard...
just look at the change control logs and see what was done prior to the issue and roll back...
Either that, isolate and investigate.
The Metropolitan Police Service is still trying to get to the bottom of the outage that prevented staff accessing some IT services nearly a month after it first emerged. The "major network issue" surfaced on 9 June preventing coppers from accessing a number of ICT services including printer services and systems access for MPS …
I'm going out on a limb, but I think they may have already thought of that... After all, it only takes one eejit to make a change without change control or not properly specifying their change in the change control system to really balls things up for everyone. I've seen it many times in heavily change controlled environments. There is always one person who can't be arsed with process.
"Whilst we understand the issue, due to its complexity, investigation will continue into its root cause. We cannot provide further detail until this work in complete".... or in police reality, It's obviously the work of some malicious hacker, we need more powers to deal with this threat to our security, and if you don't agree with us, you might accidently hit your head in our cells.
The Met uses Windows XP Pro, which works well. Although there are still print issues, we do have a backup system which allows printing, just without our individual print preferences. Considering the security requirements and restrictions with a most police applications, the system is remarkably robust.
Well, if their Canon printers behave anything like our LBP5050N they have a strong suspect.
We bought our printer in November and it hasn't worked reliably for a day since. We've had three engineering call outs, they have replaced the comms board and have just foisted some new drivers on us that make sod all difference.
Only one person in an office of 50 has managed to print to it (from XP) and to make that happen the printer has to be switched off/on as it doesn't come out of sleep mode properly.
In deperation we bought a Brother printer that sits beside the Canon and 'just works'.
After over 10 years of having HP hardware to work with I left that job went to another outfit who decided to buy Canon printers, well.... it only took me 30 minutes on each and every desktop to install a convoluted proprietary printer network driver... and that was before trying to get online scanning from the MFP's. Scanning simply won't work unless the computer AND printer are on the same physical network switch.
The Register's March 10, 2003 story on how the Baghdad air defense system was brought down by a virus hidden in a printer's EPROM (http://www.theregister.co.uk/2003/03/10/one_printer_one_virus_one/) might be a clue that more is at work here than meets the eye.