Outlook 2016 caching limit

[Vitamin-Z]

We are having an interesting issue with our Gmail to O365 migration. Mac users that have huge mailboxes (over 50GBs) or mailboxes with a large number of messages (over a million), when converted and when trying to login to Outlook for the 1st time (when we used Google no one used Outlook), their clients will crash after some time due to the size/amount of mail. Outlook is trying to cache everything and can't handle it. Is there a way to dictate how much Outlook caches, maybe via bash? I can't believe that we are the 1st company that ran into this.

Any pointers would be greatly appreciated.

[talkingmoose]

Tough love. :-)

Anyone who hits a million email messages needs to devise an email management system. Let's do the math:

1,000,000 messages over 10 years would be 100,000 messages.
100,000 messages per year would be 273 messages per day every day for 365 days in a row, or worse:
100,000 messages per year would be 394 messages per working day for 251 working days in a row.

Being generous...

273 messages per 8 hour work day would be 34 messages per hour or about one every 30 seconds.

No one can process that much mail over 10 years.

Therefore, most of this mail is junk or ignored and not needed. I can't tell you how to manage your users but they're certainly not managing their mail data.

With that said...

Outlook has a feature for Exchange and Office 365 to "Download headers only". That means only messages actually clicked and viewed are downloaded from the server. The rest would be just From, Date and Subject line, which takes relatively very little space. Enable this feature as you configure the email accounts in Outlook. Keep the mail on the server.

Also, take advantage of Office 365's Online Archive feature, which works with Outlook 2016. Your Exchange Online or Office 365 administrator can set policies to move undeleted messages to an archive mailbox that will also appear in Outlook. The beauty of this is that mailbox is never synced to the client. To view it, your users must be online and connected to Office 365. If they click a message, it downloads, but when they quit Outlook the cache is deleted. This archive space is unlimited. UN-LIM-I-TED.

This should give you more of an idea about online archiving: Use retention policies to automatically archive messages.

And before you say "this is an executive" or "this is a high traffic shared mailbox", neither of those phrases is a magic elixir that exempts anyone from needing better mail data management.

Tough love. :-)

[talkingmoose]

Aaaaaand my math is off. Should be:

273 messages per 8 hour work day would be 34 messages per hour or about one message every 1-1/2 minutes.

[scottb]

I'm with the Moose on this one - that level is insane, and I personally could care less about a client that can't manage emails better than that.

*edit - sorry, wasn't geared at the OP personally - just hate this sort of "problem" which is nothing more than babysitting...

[AVmcclint]

I agree. There are some things that technology can't solve. I've had clients using Apple Mail with many many thousands of messages in their folders and they would call me once a month to archive messages for them. When I connected to their computers and looked at the Mail app 95% of their messages were unread. I had to have a sit-down meeting with these senior level execs to tell them that these emails from 2002 (this was in 2012) aren't doing the company any good. I even randomly picked a dozen emails from their old folders right there in front of them and 3 of them were "what are we doing for lunch today?" 4 of them were of the "I agree" or "me too" reply variety. and the remaining 5 contained references to products or contacts no one could remember. I even did a sort on attachment sizes. The 50 largest emails were 50MB or more and they were other people's home movies or other non-work related files. The final nail in the coffin was when I asked them point-blank, "When was the last time you went looking for ANYTHING in any of these archive folders older than 3 years?" The answer was a unanimous "Never". After that, I deleted 7 years of unread email and all of their email crashes and slowness problems went away.

[#6]

When someone replies to me that they need to be able to find that one specific World's Most Important Email hidden somewhere among the tens (or hundreds) of thousands, I usually tell them that the time it would've taken for them to file it outside of the mail client (print to PDF, export to .eml) is much, much less than the time it will take them dealing with crashed email clients, rebuilding indexes/databases, etc.

Teach folks how to use rules and automatic processing. Remind them that 96% of all saved email is never referenced again. Tell them that if it's important, save it to the same location as the other relevant data, get it out of the email client silo and in with the Office files, PDFs, layouts, whatever.

I also try to push people - especially more senior level staff - to have a semiannual email clean-up day.

[jarednichols]

EFS (Exchange Filing System) is an ineffective method of storing anything. Technical solutions can't fix social problems.

[Vitamin-Z]

Thanks for the replies. Unfortunately I can't tell or teach end-users anything since I'm not directly involved in communicating with individuals. I was simply looking to see if anyone has a solution outside of shrinking a mailbox. Because we've been on Gmail for years most users don't care about size or amount nor did it mater. Outlook is different particularly when it comes to Macs. Looks like deleting is the only way.

[neilticktin]

I know this thread is old, but just happened upon it.

More than likely, the issue here is Gmail. It has severe limitations not found with other solutions. For example, even on paid accounts, once you've moved 500 MB of data -- you'll be throttled for 24 hours. Again, even on PAID accounts. Similarly, there are limits on the number of folders (tags) -- probably in the 600 folders range is when things start to fall apart.