It's easy to get sentimental about Windows XP and forget the hostile reception the OS received at launch — but the fact is, it's simply not cut out for the modern world, according to a senior Microsoft executive.

Despite the undeniable eventual success of XP — and the important lessons it taught the company — it drew criticism when it first appeared in 2001, says Jay Paulus, director at Windows Commercial.

"When you look back at some of the reviews when Windows XP shipped, it was reviled because it had some UI changes, it had some changes to the start menu, it changed the windowing, it put some rounded corners on things," Paulus said.

"People just hated it. They thought, 'It's such a big change. People are never going to learn' — and now look where we are."

Where we are now is XP still running between a quarter and a third of the world's desktops — more than 12 years after it first went on sale. Yet on 8 April, Microsoft ends support for the OS, leaving existing users with no further software updates or security patches.

Windows XP refuses to die, despite concerted attempts by Microsoft to replace it. Windows Vista, and Windows 7 and 8 have all failed to dislodge the 2001-vintage OS.

The company is reluctant to provide any sales figures to flesh out the scale of Windows XP's enduring success relative to its other operating systems.

Paulus will go no further than saying that it "ultimately became one of our most popular, highest market share products ever".

Extended support: enough is enough

Over the years Microsoft has tried to address the issue of people sticking with XP, despite new Windows launches, according to Paulus.

"We've extended the Extended Support timeframe so many times with XP for that very reason — to keep giving folks more time," he said.

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"But I think we've just reached the point where everyone realises that that platform was created in an era when the threats were just fundamentally different."

When XP shipped, wi-fi networks were a big deal and Sony Discman-type devices were still in wide use, Paulus says.

"At some point there is only so much you can do to patch the system until it becomes the time when you need to move onto a new foundation. Just purely from a security standpoint," he said.

"It's just from a different era. It's very popular. It established a huge user base and there's a lot of it still out there, but it is time to move that thing along."

Apart from commercial success, Windows XP has also taught Microsoft a lot about the importance of reliability, predictability and stability, Paulus says — along with the way people adapt to user interface changes given time.

"Windows XP was the first consumer OS that shipped on the Windows NT kernel, which may be forgotten at this point of time," he said.

"That's what made it so successful. Because it was on the new kernel and that kernel had been tested and proven in a corporate world, it brought a tremendous amount of stability and reliability to Windows" he said.

The Vista effect

Windows XP's enduring popularity also owes much to the shortcomings of its immediate successor, Windows Vista, which Paulus describes as "just a bad memory".

Even when buying new machines, in many cases organisations and individuals opted for the older Windows XP rather than Vista.

"Windows Vista had a number of compatibility problems. It introduced fairly large security changes, changes in the driver model," he said.

"If you were involved in computing at the time, you'll remember that trying to put Windows Vista on a Windows XP-era machine was brutally difficult because of the driver compatibility issues. Because we changed so much of the core of the platform, it broke a lot of drivers."

Windows XP's enduring popularity also owes much to the shortcomings of its immediate successor, Windows Vista, which Paulus describes as "just a bad memory".

The lessons learned from Vista about compatibility and reliability were applied when Windows 7 shipped, and help account for its present position as desktop OS market leader.

But despite the qualities of Windows 7, many have stuck with XP rather than move to more modern alternatives.

"When we talk to customers we get a few different reasons why they don't migrate — a lot of it has to do with money. People don't want to move if they don't have to," he said.

"There's a certain amount of uncertainty that drives it: 'I'm not sure what's going to happen. I'm worried about application compatibility. I'm worried about the effort and the time'.

"People get comfortable with the thing they have and it's understandable — change is hard and nobody wants to spend money if they don't have to. But we've reached that point where people need to move.

"We're pretty confident that people who move on to the modern Microsoft platforms — Windows 8 and Office 365 — soon realise that the upsides are huge and unlike Windows Vista."

Support and migration options

As to the options open to XP-using organisations and individuals, Paulus points to the free tools, guides and resources that are designed to make migration easier, as well as hardware offers from partner companies such as Dell, HP and Lenovo.

Paid-for support from Microsoft after 8 April is an option but only for larger organisations with existing Premier Support contracts.

"By and large it is only going to be the largest companies — and even for those large companies it proves to be an expensive proposition," Paulus said.

"Because in the end they're paying to have an engineering team building patches for their organisation and then delivering those patches. It's definitely designed to be a last resort."

Microsoft does not publish the prices for Custom Support, saying it depends on company size and specific requirements and is available at a few different levels — including a lower-cost form called Essentials, which requires a smaller upfront fee.

"But we're talking about thousands of dollars. It's really not designed to be a mainstream solution. We're really looking for folks to move off the Windows XP platform," Paulus said.

Standard Custom Support is for firms with 1,000 or more devices and is costed out on an annual basis depending on precise machine numbers.

"[The lower cost option] is still in the tens of the thousands of dollars to enrol, and then you pay per fix as well as a per-device fee. It allows you to scale it back somewhat, but we're talking tens of thousands of dollars on an annual basis," Paulus said.

It will be incumbent on IT departments to deploy any patches Microsoft produces for XP because there will no longer be any General Distribution Releases, or GDRs, to roll out and automatically update machines.

MSE updates: Not really an extension

Recent coverage reported Microsoft as continuing to provide virus signatures and anti-malware engine updates for XP until 14 July 2015, but it's not really an extension, according to Paulus.

"Microsoft Security Essentials is something that never really had a formal published policy on how long that would continue to happen on an unsupported OS. This was just a matter of making it clear," he said.

"The honest truth here is that they would have had to do work to stop those updates from going out."

Paulus says Microsoft thought that clarification was the right thing to do for customers.

"It gives us another good way to notify them that they are on an unsupported OS. We just want to make sure people don't get the wrong idea and think that's a reason why I can stay behind," he said.

"It's a good thing. It helps and it's the right thing for customers but they shouldn't get a false sense of security and use that as a reason to delay for another year."

He also believes that recent reports about Windows 9 shouldn't be used as grounds for delaying a move from XP.

"There's always a new release. We're always working on the next version. As soon as we ship one, of course we are working on the next version. I don't think people are confused by that — I hope that they're not because that shouldn't be a reason to wait," he said.

"People need to make this move. Right now is the time. We want as many people to move as possible before the end of support date. It's really the best option for them."