No desktop after upgrade

Upgraded from Jessie + TDE Stable to Stretch + TDE PSB. Upgraded cleanly. On first attempt TDE ran some kind of XDG compliance enforcer. TDM starts and I can log in. TDE spends half a minute or so saying "starting desktop" in the usual way but then I'm left with nothing but the cursr and a blue background. The only anomaly I've found thus far in the logs is (IIRC) an ASSERT of "primary_set" from randr. Any suggestions, tips, or hints would be welcome. Difficult to answer questions as without KMail it is taking me several attempts to type perfect headers into telnet that the list software will accept. I have recent backup as a last resort but am hoping for a way forward. Thanks, --Mike