Microsoft has re-introduced Update Rollup 1 for Windows 2000 SP4, following complaints that the original rollup caused installation problems and application incompatibilities.

The update was originally released on 28 June, with more than 50 fixes for security and reliability issues. The glitches that surfaced in the update were a black eye for Microsoft, which is trying to retire the still-popular operating system. The software company confirmed in August that it would reissue the update.

"These issues are isolated and affect few customers," Microsoft insisted in a Knowledge Base article accompanying the re-release, called Update Rollup 1 for Windows 2000 SP4 v2.

Microsoft says the re-release fixes four problems with the original update. These include two involving installation problems, a third involving the Registry Editor and a problem preventing Microsoft Word from saving directly to floppy disks.

The new update doesn't include fixes for third-party application compatibility problems, including problems connecting to a Citrix server and incompatibilities with security programs from Panda Software, RealSecure, Internet Security Systems and Sophos. According to Microsoft, these problems were experienced by so few customers that it wasn't worth including the fixes in the update.

Instead, users should go directly to application vendors for a fix, Microsoft said.

At the beginning of this week, Microsoft unexpectedly cancelled its planned "critical" patch for September, citing quality issues. This was the second time that Microsoft has changed its mind about releasing a patch since the company began giving customers advanced notification of its monthly patches late last year.

It was also the second month in a row that quality issues have marred the monthly software release. In August, Microsoft released a corrupted version of a patch for Internet Explorer, and users who picked up the patch from Microsoft's Download Center within the first few hours of its release were unable to install the software patch.