Organisations with BlackBerry Enterprise Server (BES) for Lotus Domino deployments could be affected by a recently identified bug in Research In Motion's latest BES 5.0 maintenance release (MR), BES 5.0 for Lotus Domino MR3.RIM BlackBerry Enterprise Server (BES) Downloads Page.

The bug apparently causes some messages that BlackBerry users filed into folders in the past to be dumped back into their main message inboxes after wireless reconciliation, or wireless sync.

From RIM's BlackBerry Technical Solution Centre:

"This issue occurs when a BlackBerry smartphone user has a large amount of sub folders in their mail file (more than 255). Due to the way the folders are compared between the BlackBerry smartphone and the State Database, folders outside of the first 255 do not get referenced correctly and eventually get filed back to the inbox."

RIM says it's aware of the problem and is working on a fix, but no workaround is available, nor a timeframe for when one will be.

The bug shouldn't affect users with fewer than 255 mail folders, according to RIM, and the average BlackBerry-equipped staffer probably has significantly fewer folders than that. But it's not unheard of for long time BlackBerry users to accumulate mail folders, and the BES 5.0 MR3 for Lotus Domino bug could cause some serious headaches for folks with very large amounts of folders, and their BES administrators.

More information on BES 5.0 and the above-mentioned bug can be found on RIM's website.