Seat reservations
 

Anybody else having difficulty selecting seats for their reservation?

No - can you be more specific? Are these CO flights? Are you trying on CO.com or another website?

I've got a reservation to LAS that has no outbound seating assignment. System also will not allow me to select a seat (of the very few that show on the seat selector page).

In the past, I have seen this come up most frequently on flights where there are different types of plane being used on the route and I have six to eight seats to select from if I catch the OLCI at the time the windows for check-in have opened.

CO flights, non-CO booking
 

Booked on-line non-CO, no opportunity to select seats. Linked booking to my OnePass & discovered one passenger, (4 segments but not always the same person) had seat allocated but not companion.

What happened when you tried to select the seats on CO.com?

There are regularly issues with selecting seats on 3rd party booking sites - going to the operating airline to select them is the most reliable approach.

FWIW, the issues I described occur through the CO.com page. I don't book through third party sites.

I can see my reservation fine, but I have no seat assigned for the outbound leg of the flight nor will the system allow me to select one. The return leg has a seat assigned (and gives me the option to change if I so desired).

I have seen that happen occasionally in the past - not recently though. When I've tried again it worked ok. Alternatively you could call CO and they could do it manually.