There is a case issue with some MacBooks.

Apple has started replacing the bottom case of MacBooks sold over the last year and a half.

According to the company, some MacBooks have a problem in which the rubber surface on the bottom of MacBooks separates from the underside of the computer. The issue affects MacBooks shipped between October 2009 and April 2011.

Apple is offering three free ways to fix the problem.

Apple said that it will replace the bottom case on affected MacBooks at the Genius Bar at any of its retail stores. In addition, consumers can choose to work with an Apple authorized service provider to get the new bottom case.

If those options aren't possible, consumers can opt to order a replacement bottom case kit on their own. According to Apple, MacBook owners can order the kit over the Web. The company will then send users a new bottom case, as well as a Phillips screwdriver, screws, and instructions on how to replace the part.

Apple is offering the free replacement for an indefinite amount of time. Those whose MacBooks might have been produced between October 2009 and April 2011 but aren't seeing the rubber surface separate from the case are not eligible to receive the new part.

Further reading: Apple MacBook Spring 2010 review