NEW YORK >> Internet phone service Skype says a small percentage of its 170 million users have been unable to sign in to its service, a problem that it expects to fix with a software update.

Skype said on its website the trouble stemmed from corrupted data affecting computers using Windows, Linux or Macintosh operating systems.

The company, which is based in Luxembourg, said it released a new version of Skype for Windows late Thursday to deal with issue. On Friday, it released a version for Mac. Linux users were told to delete a file manually.

Skype said individuals using its service on cellphones, televisions or other non-computer devices were unaffected.

Skype’s service, which allows users to make voice or video calls for free or for low rates, has become a popular way to lower calling costs.

Microsoft Corp., the world’s biggest software maker, is buying Skype for $8.5 billion in a deal expected to close by the end of the year. Microsoft believes Skype will help it sell more digital advertising and offer more popular conferencing tools to help businesses save money.

Skype’s services also span hot markets — online socializing, mobile phones and digital video — where Microsoft has been struggling to catch up with Facebook, Apple Inc. and Google Inc.