User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; rv:11.0) like Gecko Steps to reproduce: When I go into Account settings of an IMAP-based account then there are in "Synchronization & Storage" some "Disk Space" options: [] Synchronize all messages locally regardsless of age [x] Synchronize the most recent 30 days This way of preference does NOT explain the reference date to calculate the "30 days". 30 days from message creation date or 30 days from download message date. In other words: If I download now (by double clicking on a message line in the message list above) on an older message let say from 17th June 2015: will this message be preserved locally for 30 days too? Thats what users need! Furthermore a few words should be mentioned what happened with the local copies of the messages after the specified period. Current option view is confusing. Actual results: see above Expected results: The section options should be as follows: [] Synchronize all messages locally regardsless of age [x] Synchronize the most recent 30 days after reception and after download After 30 days local message copies will be cleaned up automatically [] Don't download message larger than x KB Pls include in next release