TurboTax Canada 2024 was working fine yesterday.

Today, on trying to start TT, I get TurboTax is unable to determine if an update is available.
TT805

Followed by "An unexpected error occurred while activating the product.

On pushing 'Activate Outside', I get "An unexpected error occurred while activating the product." again and TT closes.

I have tried re-installing but no change.

@mkswallow Please make sure that TurboTax isn't blocked by an anti-virus, firewall, or other security software. 

If you are still not able to resolve this issue, please contact our phone support team for more assistance. 

During tax season (from CRA NETFILE opening (mid-February) to the regular filing deadline (April 30), we're available 7 days a week during these hours:

• 9 AM to midnight ET for English support
• 9 AM to 9 PM ET for French support

During the rest of the year (May 1 to mid-February), we're available Monday through Friday, 9 AM to 6 PM ET for English and French support.

After phoning support, it became clear that after many years of both Kaspersky and TurboTax working on my desktop, they could no longer play together and Kaspersky had to go.