Sticking with Windows XP can be expensive but it seems leaving the 14-year-old OS can cost even more, as one German city is finding out.
Ditching Windows XP and 2000 will cost Munich City Council more than $12,000 for every employee still using the outdated operating systems.
Windows XP and 2000 are used by fewer than 1,500 of the more than 16,000 staff at the council, which relies on the aged Microsoft systems to run 41 applications.
However, still using Windows XP and 2000 creates difficulties for Munich, as neither OS is updated to fix bugs that could be exploited by hackers and the council has to take special measures to secure them.
In order to stop using Windows XP and 2000, these 41 applications will either be migrated to a newer, supported operating system, replaced with more modern software or phased out - as part of a four year project costing €16.6m ($18.03m).
The high cost of leaving XP helps explain why some organisations have paid millions of dollars to keep running the venerable OS, with the US Navy recently agreeing to pay Microsoft at least $9m to help secure computers running XP.
Munich carried on using XP and 2000 due to these 41 applications being used for crucial work in the city, from monitoring emissions for air pollution to flood protection.
To secure the OSes, Munich ran them on virtual machines and on standalone computers, as well as using what it calls "restrictive data interchange", quarantine systems and additional protective measures.
The council has decided to stop using these older unsupported versions of Windows now as, not only are they a security risk, but according to a report they have limited support for network and data security features the council wants to use.
Why XP won't die
Steve Kleynhans, research VP with analyst house Gartner, said it wasn't that unusual for pockets of machines within organisations to be running very old operating systems.
"A lot of times it's old applications that they don't have any good way to update," he said.
"For whatever reason it's not worth the cost of updating the application to a newer platform but the application is still critical for some business function."
Often it can be the case that organisations can't update the application to run on a newer OS because the people with the necessary skills are gone or the company that originally wrote the software no longer exists, he said.
"They know the application will be retired in 2016 or some future date and they're just holding on until they can actually close it down and move it out."
There may still be pockets of XP within many organisations, when Microsoft dropped support for XP in April 2014, more than three-quarters of businesses in the UK were still running the venerable OS somewhere within their IT estate, according to one survey.
"When you're a big company or a big organisation, projects don't happen quickly. You may have seen it [the end of support for an OS] coming since 2013 and said 'We're going to shut this application down because it's not worth updating it to the new operating system but the quickest we can shut it down is 2016," he said.
Kleynhans has seen organisations clinging on to operating systems from even longer ago.
"I ran into a company just a few weeks ago that was still running something on Windows 98 and it was a production system. They couldn't replace it, it did one task and one task very well. They were sitting there thinking 'What happens when the machine breaks?'"
The project at Munich will be split into two phases, the first will assess the work needed and the second will carry it out. Work got underway at the end of last year and is expected to be complete by the end of September 2019.
"The most appropriate operating system will be chosen for the applications in question," said a spokesman for the council.
"Based on the analysis of the technical and business requirements in phase one, a specification will be developed for each application, defining and describing the target platform and also the process for its migration to that platform."
Munich City Council became famous for undertaking one of the largest shifts away from Microsoft software in the world.
In 2013 the council completed a nine-year migration away from Windows NT and Microsoft Office to a Linux Ubuntu-based OS and free software such as OpenOffice. The length of the project was extended by an overhaul of the city's IT infrastructure that Munich felt was necessary to complete the work.
More than 15,000 staff were switched away from Microsoft software, with XP and 2000 kept for the handful of applications that were considered too costly or complicated to move.
The council has also commissioned an independent review of its IT infrastructure, which will consider which operating systems and software packages would provide the best value for money. The review's findings are expected to be published in the second half of this year.