Currently, it has been completed in five languages (English, French, Spanish, German and Japanese).
The company said that this service pack fixes several issues related to performance, reliability and compatibility.
The developers relied upon information received from customers through Customer Experience Improvement Program, Online Crash Analysis, and Windows Error Reporting to code this first major update to the Vista operating system.
They would now release the Windows Vista SP1 to Windows Update and their website next month. It would be delivered automatically to Vista users in April. SP1 in other languages would also be released in that month.