User Agent: Mozilla/5.0 (Windows NT 5.1; rv:42.0) Gecko/20100101 Firefox/42.0 SeaMonkey/2.39 Build ID: 20151103191810 Steps to reproduce: Menu → Tools → Set Up Sync → Create a New Account → Email Address → Invalid email address Actual results: When I start typing in my email address after three keystrokes I immediately get “Invalid email address” message.

This does not seem to be a problem on Linux 64-bit.

(In reply to Michael Pagano from comment #1) > This does not seem to be a problem on Linux 64-bit. Was the Sync service established at last? If yes, than what does this mean??!: http://www.seamonkey-project.org/doc/sync SeaMonkey Sync Attention! Starting with Firefox 29 (SeaMonkey 2.26), it is not possible anymore to set up legacy Sync accounts as described below. The new Sync back-end, which uses Firefox Accounts, is not supported by SeaMonkey yet. If you want to use Sync with both Firefox and SeaMonkey, you will need to use an older version (e.g. Firefox 28 or SeaMonkey 2.25) to do the setup. Once Sync setup is complete, you may go back to using the current versions.

I confirm, this does happen, in: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0 SeaMonkey/2.44a1 One is not prevented from continuing to enter the complete email address, but known good email addresses resulted in "Unknown Error" instead of "Invalid email address". Probably the meanings of errors should be fleshed out so the user can take appropriate actions, and if sync is not available yet the UI should make that clear somehow.

(In reply to benl from comment #3) > I confirm, this does happen, in: > Mozilla/5.0 (Windows NT 6.1; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0 > SeaMonkey/2.44a1 > > One is not prevented from continuing to enter the complete email address, > but known good email addresses resulted in "Unknown Error" instead of > "Invalid email address". > > Probably the meanings of errors should be fleshed out so the user can take > appropriate actions, and if sync is not available yet the UI should make > that clear somehow. It appears to be strictly a Windows issue, then.

This needs to be taken care of in Bug 1022319.