problem with outlook removing mail from exchange

i ran outlook for mac and had no problem till august upgrade following i noticed that the only place that had my email was on the mac itself. when i looked for my mail on the web outlook or other computers using outlook exchange i couldn't find them. i can't understand what to do to stop this as i cant use my mac at work to access my mail

I'd guess you're using IMAP in the retrieval of your email. If so you need to use the option of 'leave a copy on the server'. Where this option will be very much depends on your email provider.