Millions of the 8.5 million devices affected by a huge tech failure last week are now working again, but it might still take weeks to recover from the event.

CrowdStrike, the company behind last week’s global tech outage, says a lot of the 8.5 million devices affected are now back up and online. Officials say they’re trying a new way to fix systems faster. Experts say full recovery may take weeks.

It was last Friday that a software update from CrowdStrike wreaked havoc on devices using Microsoft Windows. Flights were canceled, TV stations went off the air, medical appointments went unplanned, and many computers just wouldn’t start.

Crowdstrike posted an update on social media saying they have made good progress in fixing the problem. They further revealed that a “significant” number of affected Windows devices are now able to operate once again. They also said that they were testing a new method that would speed up the repair process and work on making this new technique available to companies and organizations.

The home affairs minister of Australia said that CrowdStrike was close to releasing an automatic fix for the update problem. Microsoft has reportedly prepared a fix too. However, it was warned earlier that it may take a little longer time to repair the affected PCs because the repairs would need to be done by hand, and hence recovery could be delayed.

More than 1,500 flights were canceled in the United States on Sunday as the problem continued for the third day running. Atlanta-based Delta Air Lines was among the worst-hit carriers. At least 45 flights were scrapped across the UK on Saturday.

According to Delta’s CEO, Ed Bastian, the technological mishap hit a big tool the airline uses to keep track of staff. That system simply could not process all the changes brought on by the systems failure.

The UK’s National Health Service warned that healthcare services were still recovering from the outage, advising patients with appointments this week to keep them unless told otherwise. According to the British Medical Association, normal doctor services could not start immediately due to a large backlog created by the tech problem.

An NHS spokesperson stated that “Our systems are now back online. We anticipate further disruption will be kept to a minimum thanks to the hard work of NHS staff. However there may still be some delays as services fully recover, particularly as GPs need to rearrange appointments. Please bear with us.”