I have just updated my daughter-in-laws iMac - she's been working overseas and put the Mac in storage. She wanted to go straight to Snow Leopard but when I explained the scale of that, apps that will not work, number of updates required - she opted for my recommendation; go to 10.4.11 and research SL for later. This I did for her, after "cleaning" the system with Disk Utility and Techtool Pro.
All looked good, but when I woke next day, the Mail app had asked her to import Mail, this she did, but all messages say she needs to go on the Net to download. Mail is POP for this account, so it should be on the computer, and she can't download older mail that has been deleted.
I seem to remember some of these issues but it's so long ago. I've searched through my collection of MacFixit articles but can't find what I'm looking for. Does anyone remember this issue, and know if there is a resolution other than accepting it's all gone?
They don't have a backup, they don't have an extra drive. I contemplated saying we shouldn't do this without a backup but I have mentioned the need for a backup for some time and they haven't listened.
But I did the update so I must help as much as I can.

pashdej,

You might see if any of the suggestions in this article are helpful. Mac OS X 10.4, Mail: Messages seem to be missing, or 'Message has not been downloaded' alert appears when opening.

One error I made is addressed number 3, Tip; I needed to select the folder that contained my mailbox, not the mailbox itself.

FYI, an iMac that came with Panther (10.3) cannot be updated to Snow Leopard (10.6). At most it can go to Leopard (10.5).

Thanks for these insights. I wasn't sure if they had a PPC iMac or an Intel - it is a PPC, so I appreciate that there is little point even taking them to Leopard. They seem happy with Tiger.
The Mail folder is 486 Mbs in size and they say that when she first told Mail to rebuild, it said she had 4,300 messages - so I'm pretty sure they are still there, just how to get Mail to rebuild and relink them all. The article mentioned I have now read, just what was needed.
I'm hoping that I can talk them through on the phone.
Again thanks.
The old MacFixit archives, who has them?

pashdej,

See this for MacFixItForums.

You may find Kevin M. Dean's post useful: Fix for macfixitforums archive slow loading.

See this for MacFixIt at CNET.

There is a Navigate MacFixIt box on the right with an Archive dropdown menu.

The MacFixIt forums have been purchased by CNet/CBS, which closed and replaced them with the CNET Mac forums. CNet has so far maintained the old MacFixIt forums archive, but it’s not clear how long that will continue. For speedy access to this archive, the FineTunedMac thread Fix for macfixitforums archive slow loading does exactly as it says…

> I wasn't sure if they had a PPC iMac or an Intel - it is a PPC, so I appreciate that there is little point even taking them to Leopard.

For what it's worth, I skipped Tiger...stuck with Panther and only upgraded when Leopard featured QuickLook...wonderful feature.

OS X 10.5.8 also gets you access to Safari 5's extensions functionality.