Public Folders is slow after migrating to Office 365

Accordings to your topics, you may add Exchange Online
Or do you still use Exchange on premises?
Where do the public folder mailboxes reside?

My first thought was, that there may be difference between O365 Busines basic and standard...
https://docs.microsoft.com/en-us/office365/servicedescriptions/exchange-online-service-description/exchange-online-limits

But according to public folders, I do no see a differnce...
And I also cannot see a difference if users had Office 2013 or 2016 before...

You may inspect your public folder hirarchy. It is a common issues, if folders contain a lot of items (5.000 and more).
How large is the content? 

Bembi
Public Folders in on-line as well as Exchange

That public folders are an Exchange topic is clear, I want to now if Exchnage is on premises or Exchange Online. 

Online

My assumption is, that newer clients first at all need to sync the hierarchy. Dependend from the content of the public folder structure it may take a while.
Public folders has sometimes the  character that they only grow and never shrink, as nobody cleans up.
Now, moving all your clients to Exchange online, they all have to sync back the whole structure via an internet line.
Try to avoid big data graves and especially to keep the number of items in a single folder in acceptable ranges.  

You may give them some days and then see, if they get faster after a while.
Possibly let the clients run over night (Outlook open).
You may also inspect the traffic / load on your internet line.

Thanks Bembi
Our Public Folders is not large at all, like I mentioned some users it is very quick and for some it's very slow

Hello,

i can not find any hint for a difference according O365 Business Standard or Business Basic accessing public folders. They access the same hierarchy.
Is there any other difference between these two user groups?
Is it validated that only Business Basic users are affected? All of them or only a few ones?
Office 2016 is replaced by O365 as well, right?

any users that was using M.S. Office 2016 or 2019 prior to the migration and is now also using Business Basic to they can use office.com has a very slow public folders, any user that was using M.S. Office 2013 was upgraded to O365 STD these users have very fast Public folders.

Do you have clients, which never had Office 2016 / 2019 before and now using Business Basic ?

Do you have clients, which never had Office 2016 / 2019 before and now using Business Basic ?
no

I found the issue, it's an add-in from our Newforma civil engineering software that slows down our Public Folders
thanks 

Hello jsarinana,

perfect.
So its worth to close the question either by accepting an answer as a solution or to request a deletion.