I am facing constant slow performance issues in Outlook, especially when opening emails or switching folders. After checking a bit, I noticed that some of my PST files are still in the old ANSI format, which seems to be causing size limits and performance problems. Has anyone dealt with this before? Does upgrading old ANSI PST files to Unicode PST actually help improve Outlook speed? If yes, what is the safest way to upgrade the PST file without data loss?