In early November, Microsoft announced to cut the unlimited OneDrive storage for Office 365 subscribers back to 1 TB. Microsoft also announced to reduce the free OneDrive storage from 15 GB to 5 GB and to remove the 15 GB camera roll bonus.
Since this change was quite unpopular, Microsoft decided to give back some of the OneDrive storage. Click on this link by the end of January 2016 to preserve your 15 GB OneDrive storage, as well as your 15 GB camera roll bonus. This offer only applies to existing users and won’t be available to new OneDrive users. Users of the free OneDrive who do not click on the link provided above will be reduced to 5 GB in 2016.
Microsoft didn’t change its mind about unlimited storage which is why Office 365 users are still getting 1 TB storage.

Keep your OneDrive storage