We are running:

Engine: default (v1.2.3.3125)
Mobility (v1.2.3.3125)
GroupWise (v1.2.3.3083)

The Server has a 500 GB Hard Disk with 400 GB Free, We have 16 GB of memory. CPU in the server is Intel(R) Xeon(R) CPU X3323 @ 2.50GHz
We have around 120ish users on the mobility server.

OK. So I think that's all the fundamentals out of the way. I am wondering if anyone can help.

We have 3 or 4 android devices, the rest are all a combination of iPhones and iPads.

We are having an issue where quite often, some of our users have attachments that are unreadable on their iDevices. They appear on the device as 0K attachments. When this happens we have done a full resync, of the user, a resync of the individual device, and stopping and restarting the services on the mobility server itself, and none of these seem to make any difference at all to those emails. Once an attachment shows as 0k the only way to get that attachment to the end user is to resend it as a new attachment and then you have the same 95+% chance that it will work perfectly, but still have the small chance that it will not work.

It isn't down to the size of a particular attachment, or the attachment itself, if it's a spreadsheet it can be downloaded daily and work great for weeks, and then be silly 2 or 3 days in a row, it seems to be complete pot luck. Some users know now what happens and don't report it any more and just get the person to resend the original email. But, it's rather frustrating. The mobility server is fantastic. But this one frustration stops it from being perfect, and leads to a few grumbles from users, any ideas on how to resolve this, or any ideas on how to at least get the user to be able to re-download the attachments when this happens.

We can have the problem when the user is in the UK, abroad, using 3G, using 2G and even using wireless. Any ideas would be greatly appreciated.