UltraViolet is shutting down this summer — and Vudu, Walmart’s video-streaming service, is notifying customers who have used the movie-locker system to not cancel or unlink their UltraViolet accounts prior to the July 31 shutdown date, because doing so would wipe out their entire libraries.

As first reported by Variety, the Digital Entertainment Content Ecosystem — the industry consortium that managed UltraViolet — will shut down the service on July 31, 2019. First launched in 2011, the free, cloud-based service let you register UltraViolet-compatible movie or TV show purchases and then stream or download it for offline viewing from different devices.

But UltraViolet never gained broad traction on the retail side or buy-in from Disney. Its closure comes as Movies Anywhere — a similar service led by Disney with participation from 20th Century Fox, Sony Pictures, Universal Pictures and Warner Bros. — has grown since its October 2017 debut, with collections available through Apple’s iTunes, Amazon, Vudu, Google Play, Microsoft Movies & TV, NBCUniversal’s FandangoNow and Comcast.

Vudu was the biggest of UltraViolet’s participating retailers. In a notice posted Thursday, Vudu told customers that movies and TV shows they’ve linked via UltraViolet will continue to be accessible at Vudu even after the shutdown. That includes titles purchased from other retailers imported into Vudu from a user’s UltraViolet library.

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But Vudu emphasized that customers should not unlink their UltraViolet accounts from Vudu. “Unlinking your UltraViolet account before the shutdown will result in permanent loss of access to titles in your UltraViolet library,” Vudu said in the customer notice.

After UltraViolet shuts down, according to Vudu, users can continue to make online purchases and redeem unexpired UltraViolet codes through Vudu (at vudu.com/redeem) but at that point those titles will appear only in a customer’s Vudu account.

Vudu is available only in the U.S. It’s unclear whether UltraViolet users internationally will be able to migrate their collections to a service post-shutdown.

Fandango’s FandangoNow also had been a participating UltraViolet retailer. FandangoNow’s setup page for UltraViolet now redirects to a landing page to sign up for its Fandango VIP membership program.

According to DECE, UltraViolet currently has more than 30 million users who collectively store more than 300 million movies and TV shows in their libraries.