Hi,
I have a real problem which I have only just noticed.
I am an Office 365 subscriber and have been using the Outlook program on Windows PCs for years; storing old emails and calendars in multiple Outlook .pst files named by year, which I keep closed unless I am looking at a particular email or calendar event in previous years. The current setup is a Windows 10 PC running the full Outlook program from Office 365 with multiple IMAP email (.ost) accounts (three Gmail for personal or business, and my old UK BT Talk21 account that I use to collect potential SPAM emails). I also have the current Outlook Filing offline (.pst) file created by Outlook when I set it up on the PC; this Outlook Filing (.pst) file is normally left open when I use Outlook so I can move emails into it (from the multiple .ost files) to collate my emails and to minimize the size of online emails and local .ost files. Everything was working fine with my default primary Gmail email account correctly aligned with the (.ost) data file for the same primary Gmail account, particularly including the calendar and contacts for this primary email account.
Recently, I added another email account for my fiance's Hotmail emails; this account seems to have been setup by Outlook as an Exchange email account. I thought nothing was wrong because her account was working in the same way as my existing IMAP accounts. BUT I noticed after setting her account up in Outlook on the PC that, when I sent an email from my Gmail accounts, Outlook was defaulting to my fiance's contact list; I kept having to change the contact list in the drop down box to find my contacts. In Outlook Account Settings I have managed to reset my primary email account as the default for emails and contacts but I also noticed that her Hotmail Exchange account had been setup as the Default (.ost) data file (which was a real surprise). When I try to change the default data file in the Outlook Account Settings from her Hotmail account (.ost) back to my primary email account date file (.ost) I keep getting this error message:
"Mail Delivery Location" "The selected Outlook data file (.pst) format cannot be used. Outlook data files (.pst) must use the same format as offline Outlook data files (.ost). Select a matching Outlook data file (.pst) or turn off cache mode in the Account Settings."
This is wrong; all my email IMAP accounts in Outlook have been and are using a .ost file; only the associated Outlook Filing is a .pst file.
I get the same error message if I try to make any of my IMAP (.ost) files the Default data file.
I looked at (but have not actioned) setting the Outlook Filing (.pst) as the Default date file and got the following error message:
"Mail Delivery Location" "The default Outlook data file contains the calendar that appears in the To-Do Bar and settings for Favorites, shared folders, and RSS feeds. It does not change where messages are saved. Do you want change the Default Outlook Data File? Yes/No". I have said No and aborted that idea, so I am still stuck with the problem of wrong data file.
Because of the first message about turning off cache mode, I have gone back into Outlook Account Settings and turned off cache mode for her Hotmail Exchange account, which is now showing Online (rather than pointing to the still existing .ost data file). HOWEVER, Outlook will still not allow me to change the Default data file to my original primary Gmail account (.ost), even if I also open up the associated Outlook Filing data file (.pst) which is how I have normally been running Outlook.
I have tried renaming her Hotmail Exchange (.ost) data file, so that Outlook cannot find it but I am getting an error message that the file is in use by Outlook, even though the Outlook program is closed down. I know if I reboot that this will clear the problem but it will also close down this webpage where I am typing, so I will try rebooting and renaming her data file after posting this question.
So I need help; I am stuck until I get a solution to a problem that only appeared when I added a Hotmail (Exchange) account into the Office 365 Outlook (fully up to date) program on my Windows 10 PC. Prior to adding that Hotmail (Exchange) account, Outlook was correctly defaulting to my primary email Gmail account (.ost) file [or maybe to the associated Outlook Filing .pst file; I am not sure which one it originally defaulted to because I did not look until after the problem occurred; I think that it was the IMAP .ost file for my primary email account].
And I really don't want to setup Outlook from scratch again....
