I was running Office 2010 on my Windows 8.1 desktop. In Outlook 2010, I had one IMAP account. Consequently I had two pst files (outlook.pst and emailaddress@cox.net.pst).

I uninstalled Office 2010 and installed Office 2013. After running Outlook 2013 for the first time, I still had outlook.pst but instead of emailaddress@cox.net.pst I then had the following three files: emailaddress@cox.net.ost, emailaddress@cox.net(2).ost, and emailaddress@cox.net(3).ost. The Data Files tab of Account Settings shows only outlook.pst and emailaddress@cox.net(3).ost.

I’m confused and have three questions.

First, what purpose do emailaddress@cox.net.ost and emailaddress@cox.net(2).ost serve? Why were they created? Can I delete them?

Second, if I can delete emailaddress@cox.net.ost, I want to rename emailaddress@cox.net(3).ost to emailaddress@cox.net.ost and have the Data Files tab point to it. How do I do that?

Third, I have a personal cloud (Drive Y: ). Outlook.pst is on Y: but the three ost files are on C:. I want to move the ost file to the Y: drive and have the Data Files tab point to it. How do I do that?