United Airlines’ weekend migration to the Hewlett Packard SHARES system used by Continental, its merger partner, got mixed reviews: As Henry Harteveldt, an analyst at Atmosphere Research Group, said, it was “a success on the technology level but less of a success on the customer-experience front.”

In the final major step in the integration of the two carriers, United successfully moved its reservations, inventory control and departure control systems off the Apollo platform, where they had resided for more than 40 years, and onto SHARES.

As might be expected in such a massive undertaking, the transition was peppered with glitches, particularly on the first day. But although there were some delays, cancellations and missed connections, there was no systemic failure.

The migration began in the early hours of March 3. United had rescheduled some departures in Asia to avoid the period when the systems would be unavailable.

When planes began taking off later that morning, there were higher-than-usual delays at Chicago O’Hare, San Francisco, Washington Dulles and other airports, according to FlightStats.com. Those issues were largely resolved by the following day. Dulles took an additional day to recover fully, however.

Harteveldt, who traveled from San Francisco to Newark on United on March 4, said he saw nothing out of the ordinary at either airport.

United’s move to Continental’s website seemed to generate many of the customer-facing issues. Some passengers could not check in online, a problem that was compounded by malfunctioning kiosks at airports.

Some Internet Explorer users who tried to use the website received an error message: “To access the site, your browser must support 128-bit encryption with a strong cipher.” United said that issue has been resolved.

For passengers, one of the most distressing issues was the disappearance from the website and the United mobile app of flight segments or entire trips planned for the immediate future.

Some seat assignments, upgrades and upgrade credits also disappeared in the transition.

Several travelers reported their problems on Twitter and were told to call customer service. But United’s call centers were overwhelmed, despite bringing in extra staff over the weekend. Some callers reported hold times of more than an hour, and some said they were cut off after lengthy holds.

Many tickets that had been upgraded with a Global Premier Upgrade, Regional Premier Upgrade or a Mileage Upgrade Award displayed a message saying, “A modification has been made to your itinerary. Please contact United Reservations to have your ticket reissued.”

Again, United recommended on Twitter and on FlyerTalk.com, a frequent flyer forum, that passengers whose travel was imminent call the airline to have the reservation updated, an option that was often fruitless. Harteveldt said that was “inexcusable.”

Many travelers took their questions and pleas for help to United’s Facebook page, but the carrier offered few responses.

The combining of United Mileage Plus accounts with Continental OnePass accounts did not occur automatically in every case. United said it was still working to combine them.

United has sent new MileagePlus credentials to a few passengers, but most have not received them. For members of both MileagePlus and OnePass, the OnePass number survives as the MileagePlus number.

Those who belonged only to MileagePlus are being given new numbers, and some are still confused as to how to log into their accounts.

Meanwhile, Continental Airlines has flown into history. United employees worked to remove the last Continental signs from airports over the weekend.

The last flight, CO 1267, departed Phoenix the evening of March 2. It landed in Cleveland early Saturday morning as UA 1267.

But as one Facebook member noted, “It’s the Continental website, the Continental systems, the Continental policies, the Continental pricing, the Continental elite program, the Continental inventory management, the Continental logo, the Continental CEO and the Continental board of directors. The only thing that is United anymore is the name. This is Continental, people. United is gone.”