The cable car that runs from Chamonix to Planpraz at 2000m closed this week after a mechanical problem. It will be closed for maintenance until further notice. This will affect anyone doing the full Tour du Mont Blanc circuit & intending on using the table car on the first & last day.
Up to date information can be found on the Compagnie du Mont Blanc website: https://www.montblancnaturalresort.com/en/infos-live#b4
Until the cable car is reopened an alternative route will need to be taken on the first & final day. Options could be to walk up to Plan Praz from Chamonix but this would take an additional 2 hours or alternatively plan an alternative lower route to Les Houches. If you take a look at the map there are many options available.
This could also affect the final day but again there are many options to descend on foot to Chamonix.