I have a user or two who seem to be connected to _everyone's_ mailbox.  This person is in recruiting, so access to other people's calendars is necessary for scheduling.

Problem is, she faces multiple Outlook slow downs and lock ups on a daily basis.  She recently showed me a problem where calendars that she typically has access to now prompt her to "ask them to share their calendar" messages (reboots will fix this problem, for the most part).

Taken her on and off cached Exchange mode.  We have disabled the "Download shared folders" setting, and that helped some, but issues still persist.  She is typically the only one with constant problems (her and one other person that is in a similar situation).

More info: we allow Reviewer permissions for everyone's Calendar for the "Default" entry.  So, she does not have full access to any one's mailbox.  She's just viewing everyone as a shared calendar.

Hoping there's someone out there with similar issues that have successfully tackled this problem!

Running on-prem Exchange 2013 with three member DAG.

Thanks in advance.

She can use the scheduling assistant to check availability, there is no need to have other people calendars added. Remove all those calendars, compact the data file, and educate her on how to properly use Outlook. Here's a reference article: http://blogs.technet.com/b/ewan/archive/2012/02/10/tip-o-the-week-96-reining-back-outlook-s-file-size.aspx