When you try to open Outlook on a computer with two or more user accounts, you may receive the following error.
Outlook will work normally with the user account that first added an email account.
Outlook is attempting to open the OST or PST file associated with that first account. Since users do not normally have permission to read files belonging to each other, Outlook cannot open the OST or PST file.
Open the Control Panel and select Large Icons under View by.
Search for the option named Mail or Mail (Outlook 2016) and click it.
Click the third button, Show Profiles…
Click the Add button in the middle of the window.
Insert a name for your new profile. This can be anything, but it’s a good idea to use the name of your user account. Click OK once you’re done.
You’ll be prompted to add an email account. Configure it accordingly or click Cancel to add one later. In this later case, you’ll receive this message. Click OK to create your new profile.
Select the profile you’ve just created in the drop-down box under Always use this profile. This setting is applied on a per-user basis, so your other user accounts are unaffected.
Click OK and open Outlook. If you haven’t configured any accounts yet, you’ll be asked to now.