Windows Vista Ultimate Service Pack 1 (SP1) will be initially available only to users who have installed certain language packs, Microsoft has revealed.

The company said that delays in updating more than 30 bonus language packs will mean that those using Vista Ultimate with 31 language packs must wait for SP1's "second wave" before installing the update. However, Vista Ultimate users running the English, French, German, Japanese and Spanish language packs should be able to get SP1 in the middle of March.

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Microsoft offers Vista Ultimate 'Exclusives'

"We will be releasing Windows Vista SP1 in two 'waves'," Microsoft program manager Nick White in a post to the Vista team's blog.

The warning wasn't completely unforeseen. A month ago, when Microsoft said it had wrapped up release to manufacturing (RTM) and was shipping SP1 to duplication, it also spelled out a rough calendar for release. According to that timetable, Ultimate SP1 would appear as an optional download on Windows Update this month with just the five languages, as an automatic update mid-April, and the full 36 packs sometime next month, presumably after the mid-point.

Nor is this the first install glitch caused by the language packs. Last October, Barry Goffe, the director of Vista Ultimate, noted that users had had trouble installing the add-ons, and said an install component had been patched to fix the problem.

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