avatarby John CallahamJanuary 11, 20170 comments

Apple now says a bug in its Safari web browser was the reason why Consumer Reports encountered inconsistent battery results when it recently tested the new MacBook Pro notebooks. Those test results caused the well known consumer testing group not to recommend the notebooks.

In a post on the group’s website, Consumer Reports said it sent the original test results from the MacBook Pro to Apple ahead of posting them in late December. After that, the group sent over “multiple rounds of diagnostic data” to Apple, at the request of the company.  In a statement, Apple said:

We learned that when testing battery life on Mac notebooks, Consumer Reports uses a hidden Safari setting for developing web sites which turns off the browser cache…. We have also fixed the bug uncovered in this test.

Consumer Reports says it turns off browser caching as part its standard notebook testing. It says it does this because it wants notebooks to bring up new content from websites, rather than have the laptops access cached content from their local storage, so it can stress the batteries harder. The Safari bug fix is currently available for OS beta testers, and Apple plans to release the patch for all new MacBook Pro owners “in a few weeks”.