I have connected hotmail and transfered mails to my local pst file. after I remove hotmail account I don't see the mails from my local .pst file anymore
It sounds like you configured Outlook to access your Hotmail account originally with an IMAP connection. This could cause Outlook to remove the mail files from the PST when you detached the Hotmail account. I would recommend setting up Outlook with POP access to your Hotmail account. You can then set Hotmail to redownload all files from a certain date and on or all mail items. Configure Outlook to leave messages on the server. Once you remove the Hotmail account from Outlook, the emails will remain.