I’ve been twitchy about Lenova since they got caught selling computers with a rootkit that reinstalled crap-ware that users had uninstalled. A user would uninstall useless software from their computer, and when they rebooted, the rootkit would kick in and reinstall the bloatware.

The “rootkit”-style covert installer, dubbed the Lenovo Service Engine (LSE), works by installing an additional program that updates drivers, firmware, and other pre-installed apps. The engine also “sends non-personally identifiable system data to Lenovo servers,” according to the company. The engine, which resides in the computer’s BIOS, replaces a core Windows system file with its own, allowing files to be downloaded once the device is connected to the internet.

But that service engine also put users at risk.

In a July 31 security bulletin, the company warned the engine could be exploited by hackers to install malware. The company issued a security update that removed the engine’s functionality, but users must install the patch manually.

They had previously been caught selling computers with adware installed on them.

Earlier this year, the computer maker was forced to admit it had installed Superfish adware over a three-month period on new machines sold through retail channels. The adware had the capability to intercept and hijack internet traffic flowing over secure connections, including online stores, banks, among others.

Users were told they should “not use their laptop for any kind of secure transactions until they are able to confirm [the adware] has been removed,” security researcher Marc Rogers told ZDNet at the time.

It was thought as many as 16 million consumers and bring-your-own-device users were affected by the preinstalled adware.