The company, in a filing with the Securities and Exchange Commission Thursday, said the Change Healthcare business, which provides prescription processing services for pharmacies, had been compromised by bad actors. In an update on its website on Friday morning, just before 10:00 a.m. ET, the company said it was still trying to address the matter.

“Once we became aware of the outside threat, in the interest of protecting our partners and patients, we took immediate action to disconnect our systems to prevent further impact,” it wrote. “At this time, we believe the issue is specific to Change Healthcare and all other systems across UnitedHealth Group are operational. The disruption is expected to last at least through the day.”

(The company has posted the same update regularly since 11:30 a.m. on Thursday every few hours.)

UnitedHealth says it believes the intrusion was specific to Change Healthcare and all of its other systems remain operational.

With that system offline, though, some pharmacies are unable to process prescriptions to insurance companies, which allows them to receive payments. GoodRx, on Twitter/X, alerted customers they might face outages on Thursday. And the Website of the Camp Pendleton Naval Hospital warns patients that getting their medications will be an extended process for a while.

“Naval Hospital Camp Pendleton and associated pharmacies will provide outpatient prescriptions through a manual procedure until this issue is resolved,” it wrote. “Priority will be given to urgent prescriptions followed by routine prescriptions as manning and resources allow. We apologize for the inconvenience and appreciate the patience and understanding of our beneficiaries while it takes longer than usual to safely fill prescription needs.”

UnitedHealth shares were not impacted by the hack on Friday, trading slightly higher. The company told the SEC it “has not determined the incident is reasonably likely to materially impact the Company’s financial condition or results of operations.”