Thunderbird is the best e-mail program for Windows users, and the portable version is the best version of Thunderbird.
On August 31st I explained why I think Thunderbird is the best client-side e-mail program for defensively thinking Windows users (see There is only one e-mail program). Earlier the same day I discussed my personal e-mail backup scheme (Backing up e-mail). Here I'll tie both these previous postings together.
To begin with, a portable application is one that does not need to be installed. The entire application exists in a single folder. It does not store anything in the Windows registry or a Windows system folder.
Typically, portable applications go hand in hand with flash/thumb/pen/USB drives, but this is not a requirement. You can run portable applications off your C drive or any internal hard disk partition. In fact, doing so makes them run faster.
While portability is the prominent, public, sexy feature, to me, being able to backup an application is just as important, if not more so. You can back up a portable application simply by copying a folder. It is impossible to back up a normally installed Windows application because pieces of it are scattered all over the place. To get around this, you're forced to do disk image backups, which are a big hassle.
The flip side, uninstalling, is another advantage of portable applications. You get rid of a portable application simply by deleting a folder. No fuss. No muss. In contrast, it can be next to impossible to erase all traces of a normally installed Windows application. If nothing else, it's very common for junk to be left in the registry after uninstalling.
A portable Windows application can either be created that way originally or the portability can be retrofitted onto it. John T. Haller makes portable versions of normally unportable open-source applications at www.portableapps.com. Like the original, the portable version is free.
If you use more than one computer, the advantages of portable applications that can be transported on flash drives is obvious. However, even if you only use a single computer, being able to simply and easily backup an application is reason enough to opt for a portable application. The simple backup of a portable e-mail program is especially important.
Your e-mail program has three different types of data; your mail, your address book and your settings for things like the POP3 and SMTP servers. Backing up these different types of data with a normal Windows e-mail program, such as Outlook Express or Eudora, can be a real pain.
You can try to back up the files where the various types of data reside, but finding them all is error prone and the locations may change with new releases. Your e-mail program may have an Export function, but the ones I've seen have a different function for each type of data. None of these problems exist when backing up a portable e-mail program such as Thunderbird.
Copying a single folder copies your e-mail, address book, settings and more. More? Let's not forget it also copies the application itself and any changes you might have made to the user interface (Thunderbird is fairly customizable) and, in the case of Thunderbird, any extensions you might have installed. As an old commercial put it, I can't believe I copied the whole thing. :-)
You can download the portable version of Thunderbird from portableapps.com. According to the Web site, it runs under Windows 98, Me, 2000, XP and Vista as well on Linux/UNIX with assistance from the Wine program loader.
The downloaded file is currently named Thunderbird_Portable_184.108.40.206_en-us.paf.exe. When you run it, an installation wizard starts. Agree to the license agreement, and select a folder. The wizard instructions about the folder are to "Choose the folder in which to install Mozilla Thunderbird, Portable Edition". The wording is unfortunate as you are not installing the application, just un-compressing it. The wizard extracts a bunch of files and ends.
The folder you pointed the wizard to now has a sub-folder called ThunderbirdPortable. To move or back up your copy of portable Thunderbird, this is the folder you move or back up. Everything you ever wanted to know about portable Thunderbird is in this little folder.
As evidence that nothing was installed, you'll notice there is no icon for portable Thunderbird on the Windows desktop, no entry for it in the Programs or All Programs list off the Start button and no entry for it in the Add or Remove Programs applet in the Control Panel.
That's the good news. The bad news is that you have to make your own shortcut for it. In the ThunderbirdPortable folder is a program called ThunderbirdPortable.exe. Create a shortcut to this EXE file and copy the shortcut anywhere you'd like (the Windows desktop is a good starting point). The first time you run portable Thunderbird, it behaves like any e-mail program the first time it's run, you have to set up a new account.
To reiterate an earlier point, portable applications run just fine from the C disk, they are not married to flash/thumb/USB drives. In fact, they run faster from an internal hard disk. Trust me.
I've run across only one down side to using portable Thunderbird as your main e-mail program--making it the default e-mail program in Windows. That is, making it the program that Windows invokes when you click on an e-mail link in a Web page. Since the program was not officially installed, Windows barely knows that it's there. This has still got me stumped.
Update: Portable Thunderbird is also available from download.com. September 4, 2007.
Update: Replying to reader comments/questions September 4, 2007
The portable version of Thunderbird updates itself the same way as the normally installed version. Of course, updating any application can cause problems and this is where portable applications shine - you can make a full backup of portable Thunderbird before updating it.
I updated version 1 of portable Thunderbird many times without incident. However, I waited a long time to move from version 1 to version 2 and by the time I ran that update, it failed. But, I had a full backup, so the failure didn't slow me down. Some day, I'll deal with this, no rush though.
This story does however, illustrate the big problem with free software - the lack of technical support. I'm on my own to deal with this problem. A posting I made at the official forum was a waste of time despite including a screen shot of all the error messages.
As for the Lightning calendar add-on for Thunderbird, I haven't tried it. I prefer my email program to only do email. Just keeping that alive and well can be hard enough (see above), no need to complicate things.
The supported operating systems for Portable Thunderbird are listed in the posting. Windows Mobile was not one of them.