The Russian cybersecurity company says it's been notifying users of the change and is aiming for a smooth transition of software.

After U.S. ban, Kaspersky's American customers were automatically migrated to UltraAV antivirus, in some cases without the customers' knowledge.

Some US-based users of Kaspersky antivirus products have found their software replaced by product from by a low-profile entity named "UltraAV" – a change they didn't ask for, and which has delivered them untested and largely unknown software from a source with a limited track record.