Windows XP Service Pack 2: Will it cripple your network?

While the eagerly awaited XP SP2 has finally got its release date, it looks like Microsoft's crown jewels of security revamps - thought to be costing the software behemoth $300m - could cause businesses as many headaches as it cures.

Many businesses may find installing the service pack plays havoc with their custom-built software as well as bought corporate applications, for example, as their systems are reconfigured by SP2.

It's a problem that has already hit two of the industry's heavyweights - Microsoft and IBM. IBM has apparently posted an article on its corporate intranet requesting its users not install SP2 for fear that it may be incompatible with some of Big Blue's apps.

In the memo to employees IBM's internal technology department stated that Windows XP SP2 will "change the behaviour of Internet Explorer and cause some application incompatibilities." The memo also noted that some "high-profile, business-critical applications are also known to conflict with SP2."

Redmond has also had to issue a fix for its CRM products to stop it falling over when Service Pack 2 was installed on machines running the programme.

While IBM will neither confirm nor deny the existence of the request to not install the service pack, with a representative saying only "IBM will not confirm the authenticity" of the report, IT managers could do well to be cautious in installing the pack.

James Governor, principal analyst at Redmonk, said that SP2 "will potentially break many home-grown corporate apps [because] they will have been written expecting open configurations and open ports". In addition, he said "new boxes shipped by OEMs with SP2 onboard will break these apps" because of their tightened-up security configurations.

Pete Smith, director of IT and telecoms at Inmarsat, said the company won't be rushing headlong into installing the service pack.

"Understanding exactly what's in the service pack and how stable it is will be our first priority. As soon as we have confidence that it does not have any problems we will implement it to all XP users. However, like most companies we have a mixed desktop environment and updating only XP users only protects some of our clients."

While Microsoft has put two release candidates - like SP2 with the stabilisers on - in the hands of developers, IBM's memo shows that not every big company has tried backward-compatibility testing on their applications yet.

Paul Randle, Windows XP product manager, said Microsoft has had very few reported compatibility issues with Service Pack 2 in the one million downloads it has registered of SP2 in its previous incarnations.

"Testing has been enormous… in the vast majority of cases, there's been no issue whatsoever," he said, adding that a stance like IBM's was exactly the right one. "The IBM approach is very sensible - it's looking at the deployment in a very controlled way."

CNET News.com's Martin LaMonica contributed to this report