I am a self-employed accountant, and my Microsoft Outlook emails contain important advice or comments that I would like to be able to organise and store on my hard drive for future reference. At present, I keep all my emails in my in and sent boxes. I occasionally save individual emails in client folders with Word documents etc but they become overpopulated.
Keith Knowles
There are lots of add-ons for Outlook, and the one that sounds most suitable is QuickFile 4Outlook (addins4outlook.com), which you can try as shareware. There is a special version for lawyers that's also worth a look: it may meet your needs, and there's an online demo (outlook4lawyers.com).
A newer plug-in is Xobni, which is 'Inbox' backwards (xobni.com). This is less oriented towards files and more about managing relationships (clients).
Another solution is AskSam (asksam.com), which limits your exposure to scary Outlook PST file problems. I've mentioned it a few times, but often feel I must be the only user. It's a sort of free-form database into which you can chuck almost anything: emails, Word documents, PDF files, web pages, spreadsheets etc. You then have one file per project (or client), which allows fast, sophisticated searching. There's a 30-day trial version. You'd probably find you loved it or hated it within 30 hours.
However, nowadays, it's probably easier just to sort files into lots of subdirectories and use Google Desktop Search.
Backchat: Andy Slade says my answer seems over-complicated, adding: "Outlook will allow Keith to do what he wants by a simple configuration: for each of his required group of emails he can create a PST folder with a location at a convenient place on his hard drive. Then, using the Rules Wizard, make sure that the appropriate emails are directed to these folders. In this way he has an organised arrangement for his emails that are automatically saved in as many files as he wishes on his hard drive. These can be restored when he wishes and can be turned 'off' when he no longer requires them."