United Airlines was forced to ground all their mainline domestic flights this Sunday evening due to an IT issue related to the ACARS aircraft communications system.
Operations have since resumed but travelers were still affected by long delays and cancellations resulting from the hour long grounding of the fleet.
The airline has just updated their customers via twitter that operations have resumed but also mentioned that delays are likely to be be expected.
United has put a travel waiver in place for those affected passengers who wish to change their flights.
The change fee and any difference in fare will be waived for new flights departing on or before January 25, 2017, as long as travel is rescheduled in the same cabin (any fare class) and between the same cities as originally ticketed.
If your flight is cancelled keep in mind that you can demand United to re-book you onto an alternative flight even if operated by a different carrier.
I suggest to check if your flight is impacted by this problem and depending on the severity of it decide what the best course of action is. If it’s a minor delay then maybe just sit it out. Should the flight be cancelled check if there are other flights of different carriers available. Unfortunately due to this issue taking place on Sunday evening the options are often limited but flights departing from the West Coast or Hawaii could still be in range in case you are on one of those.
You can expect receiving some sort of compensation from United Customer Relations but probably have to write in for that. Some airlines such as Delta compensate passengers automatically during system wide outages but I haven’t heard united doing such a thing. United does however have the ‘Appreciation’ site (access here) where you can punch in your flight details and see if it credits you something if the flight has been entered as eligible for compensation.