Exchange Online - Refresh extremely slow and times out before completion

[heidicroft]

We have a very small dataset that only pulls from two microsoft exchange online mailboxes and two excel spreadsheets.  It cannot complete a refresh without timing out.

I've tested different options to see what could be causing such a slow refresh.  I've been able to find if I don't expand anything from the mail file, it refreshes quickly.  We do need to see the sender address and the category, so not expanding these columns is not an option.

Has anyone else run into this?  Any suggestions for a work around or different approach to get these items?

[lbendlin]

We do need to see the sender address and the category, so not expanding these columns is not an option.

That is unfortunately a costly operation.  Any lookup/expand step will slow you down massively.

See if you can fetch the user object separately and then do the join in the data model. 

[heidicroft]

Thanks. I typically don't pull associated columns, but the only connector I can find for Exchange Online doesn't give you any other options.