The following is just the result of a bit of googling but I hope that it might help:
If you CAN actually get into Outlook at all, do the following:
Click File → Options.
Click Add-ins.
Select the ESET Outlook Add-in from the list of add-ins and then click Go.
Deselect the check box next to ESET Outlook Add-in and confirm by clicking OK
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If you CAN'T get into Outlook, try Safe Mode. Follow the instructions which you can view by clicking on 'Start Outlook in Safe Mode and disable add-ins' here:
https://support.office.com/en-us/article/i-can-t-start-microsoft-outlook-2016-2013-or-2010-or-receive-the-error-cannot-start-microsoft-office-outlook-cannot-open-the-outlook-window-d1f69da6-b333-4650-97bf-4d77bd7abb85
However you probably won't need to go through all of the stuff there about disabling all your add-ins and then trying them out one by one. You already know which add-in is causing the problem, so simply follow the instructions in my first section above to disable the ESET add-in. (Once you've done that, restart Outlook).