You may notice that all of a sudden you can recieve mails but cannot send. Outlook will popup a message saying ‘Outlook data file cannot be accessed (error 8004010F)‘.

Thou the PST files are there and accessible, the only way to fix this is to re-create your Outlook Profile from the Control Panel by:

Open Control Panel
Open Mail 32-bit
Click on Show Profiles
Select the profile in question
Click Remove

Now open Outlook and reconfigure the account. This should fix the problem

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