Yet Another Missing Email Thread

[DrewD]

Hello,
I'm having email in Outlook disappear from my inbox, and so far I've found about a thousand causes for this online, and none of the solutions I've found help. Here's what's going on:
I have two computers running Windows 7. Computer A is 64-bit, and Computer B is 32-bit. A runs Outlook 2010 64-bit, and B runs Outlook 2007 32-bit. They both connect to the same Exchange server. Computer B has no issues whatsoever, it works great. But computer A has messages show up for about 2 minutes before they disappear, not to be found in any folders. I've already unsuccessfully tried the common solutions:
*I have no filter applied
*There are no rules applied
*The data file is .ost, and set as default
*I'm using the Compact view with no modifications

Any ideas? What's left to go wrong?