I only have one account.  No need to transfer registrations between accounts.  The existing account just has a very old e-mail address, which I want to update.

I got an e-mail notification of your reply to this forum (sent to the current/old address), so that much is working.

Hmm.  The page I see when I follow the link you posted says, in part:

"Source Account

This is the account that you are moving registrations from. You will no longer have any registrations left in this account once you complete this process.

Destination Account

This is the account that you will use from now on. Your other account will not have any registrations once you complete this process."

That certainly implies that multiple accounts are involved.  I neither have nor want an "other account".

The link I posted (https://www.stardock.com/accounts/accountinfo) is a simple account maintenance page, and has a section that says:

"Change Email Address"

with a field to type in the new e-mail address (twice).  This seems to be exactly what I want to do.  However, after typing in the new e-mail address and clicking "Update", it tells me that I will need to confirm the new address via a link sent by e-mail.  No such e-mail has arrived.

I believe I'm on the right part of the site.  It just doesn't seem to be working.

Interesting.  While I don't have an *account* for the new address, I do have a *purchase* (of Fences) associated with the new address.  So maybe that's getting in the way.

I used the link you posted earlier to move the purchases from the "new" address to the account associated with the "old" address.  (Going the other way didn't work, because there's no stardock account there.)

I figured this out by using https://www.stardock.com/support/product-key-retrieval to retrieve product keys from the "new" address.

I imagine something in the e-mail change system got confused by the presence of an existing non-account address.  I still can't change my e-mail address with the account info page, so that might require manual intervention.