JDybo,
your music friend's previous employment is irrelevant as his advice to you (or your interpretation of it) is completely wrong. Mail stored on any internet connected server can be accessed from any machine anywhere that can log onto the server. That is not the same as using a web based mail interface, which is what you suggested we should be using based on your friend's advice. Using a locally hosted email interface does not reduce accessibility, quite the contrary!
For example, my mail is stored on a Microsoft Office365 server. I collect it using a POP3 protocol using Outlook on my PC, the mail apps on my iPad, mobile phone, Samsung tablet and even my Kindle, again all using local storage. Similarly, all of those apps send email from the local storage to the server using SMTP protocols. Other communication protocols are available, each with their advantages and quirks. On all of those machines however, I can browse, read and write emails whether or not they have an internet connection at the time, because the email is stored locally on the machine and then synched with the server when a reliable connection is next made.
Moreover, emails which may take 10 minutes or longer to compose only require an Internet connection lasting a few seconds to move on or off the server. Similarly, I can browse through months or years of emails to find the relevant communication without any Internet connection, write an update or reply, and it will be sent from the local outbox within a few seconds as soon as an Internet connection is made.
In the case of my PC using Outlook, the local storage for emails (and address lists, schedules etc.) is an encrypted .pst file, which is where this discussion started: how to avoid conflicting access to the local storage file. If Outlook was set up as an exchange interface then the local storage would be a .ost file.
I could also use a web based mail interface, and Microsoft even provide a free one (in fact, inherited from Hotmail when they were acquired) just as you (or your friend) recommend, without any local storage. However, using that method, no access to emails is possible at all without an Internet connection and that connection must be stable and reliable for the time it takes to read and write each message, unless you are happy to spend most of the time reloading rather than actually working. And good luck browsing through years of communications with only a web mail interface. It is a bit like using this forum: no Internet connection, no reading posts, no writing post, simply no access. As such, a web based email interface is significantly inferior in almost every way and that is why your friend's recommendation (or your interpretation of it) is completely wrong.
Probably the only time webmail is useful is when you have to resort to using a public machine, and I consider my personal email as deserving much more security than that. Perhaps you should too!
