Why is an IMAP Inbox Only Displaying 10,000 Items When There are Many More Emails on the Server?

Are the yearly folders you moved emails into synced too or did you create them in outlook and never sync them with AOL? I created mine on yahoo and used yahoo to do the move and left them syned. I also made 4 per year and won't make a bew one till I havd a full quarters worth of messages to move into it just once. That way once the index for that folder is built, it should requiredand maintenance and easilyis synced between my various client apps. I haven't seen any additional load on my pc (win10 pro workstation) caused by maintaining those folders. Does take Outlook a bit longer to load cold start getting the profile into mem. Mobile app has been fine. Only problem know seems to be the junkmail filters can't seem to do their job.

ok thanks; and do you only see this cycling with the export.imap.aol.com endpoint?

I'll respond to your question about cycling.

I moved messages by years but left what has now climbed to over 30K messages in the main inbox.

Cycling: periodically some/all of the folders empty out and start over... in some cases it was over and over. My PC was overheating from all of that.

I have mostly been using outlook/AOL with the export IMAP address, on my Win10 PC (still haven't moved off the WIn7), and it's been holding ok. I just tested the WIn7, and see that the inbox was down some 10K and climbing back up -- it goes down to 1000 or maybe even zero. I have at times noticed those under 10K extracted inbox subsets were down to 1000 (all of them, and holding until other folders rebuilt. Other than that it's unlikely to catch one at the small size because it starts building.

It also wreaks havoc with the index (I moved to outlook for AOL mostly for the power of the search index), and it keeps wiping out; I have a small folder I do a search to list select messages, and it shows nothing because it got removed from the index (I think the index is emptied and rebuilt). This is a folder with 58 messages. Not sure if it empties and rebuilds; it's so small that unless it is behind others, I'd never see it. But as I said, its index entries go away.

So at least for WIn7, it is still recycling.

Thanks for the great info and feedback. I guess I'll report how I sorted myself out. I just gave in to the idea I needed to better organize my inbox and 10K was actually reasonable for a single container. Afterall, outlook will easily search across all inboxes. It took me a few night sessions using the Yahoo web interface to move messages from each year into Quartey labeled folders, let Outlook sync those and use filters and the unread views to clean up a bit. I ended up getting 10 years of messages neatly organized in a way that will be easy enough to keep up with moving forward. The biggest pain of this was that the Yahoo interface was limited to only so many headlines per page dump and it could take a while of paging down to load more from the search and then do the move. It sure would have been nice if they had a way to move all messages based on the search results rather than just what was delved into the browser memory. The Dev setting you mentioned likely is part of the interface API. I feel like it was loading 50 to 100 messages per scroll down. But for the effort I'm pleased and better off for it.

I downloaded Thunderbird because I thought I saw a post here that said it didn’t limit posts but it did limit me to 10,000 emails from Yahoo. I think the problem is with Yahoo.

When I contacted Yahoo a few months ago, they told me to use their app on my phone or to log into their Yahoo Mail site and I would be able to search my emails. I have over 100K in my inbox so I don’t know if I can see all of them on my phone but I was able to get to the ones I needed for a legal matter.

Hope this helps