Known Provider Limitations
Here is a list of limitations imposed by email providers that you should be mindful of during your acquisitions. These limitations are not specific to FEC but apply globally to all email clients.
Yahoo and AOL
Overall Acquisition
Yahoo/AOL caps folder listings over IMAP to 100,000 items per subfolder. FEC can bypass this cap when the "Yahoo/AOL Folder Cap Bypass" option is selected.
In-place Search
We have found that Yahoo/AOL is capping in-place search results via IMAP to 1,000 items per subfolder. You can work around this using Inline Search or by acquiring the entire mailbox and searching it post-acquisition.
Graph API
When using the "search" query parameter, Graph API limits search results to 275 items per subfolder. To work around this limitation, FEC defaults to using the "filter" query parameter with Graph API. It is also possible to use EWS or IMAP on Microsoft accounts where applicable. You can also work around this using Inline Search or by acquiring the entire mailbox and searching it post-acquisition.
On-prem Exchange
Some versions of on-premises Exchange 2013 Enterprise and Standard cap In-place search results at 250 items.
Potential workaround—according to Microsoft's support article, the issue can be resolved by installing an update and making a configuration change. You can also work around this using Inline Search or by acquiring the entire mailbox and searching it post-acquisition.