It’s good news for a lot of Google Chrome users, bad news for developers who don’t know how to play by the rules. All Chrome web browsers that mine cryptocurrencies are now banned from the Google Chrome Web Store. The decision was made in an effort to prevent cryptojacking, the practice of using a target computer for multiple mining operations. While Google wasn’t opposed to Chrome extensions that mined crypto, it had placed limits on the functionality. Developers had to describe the mining activity, had to agree that the extension’s only purpose was to mine, and the extension could only conduct one type of mining operation. When Google discovered that the vast majority of developers weren’t playing nicely—90% of them, in fact—it decided to pull the plug. One such extension is, or was, Archive Poster. According to its description, it was a way for users to easily interact with posts on social media platform Tumblr. However, the extension was found to participate in cryptojacking activity, mining the altcoin Monero. It has now been removed from the Chrome Store. There are many reasons why Google’s decision is necessary. Apart from the deliberate attempts to bypass controls, cryptojacking extensions can slow down computers, increase the amount of electricity that the computer uses and, sometimes, even cause computer batteries to melt from overheating. The entire time, the user is unaware of what’s going on and has never agreed to participate in the mining activity. In making the announcement of the ban, the company’s Extensions Platform Product Manager, James Wagner, said, “The extensions platform provides powerful capabilities that have enabled our developer community to build a vibrant catalog of extensions that help users get the most out of Chrome. Unfortunately, these same capabilities have attracted malicious software developers who attempt to abuse the platform at the expense of users. This policy is another step forward in ensuring that Chrome users can enjoy the benefits of extensions without exposing themselves to hidden risks.” Any extensions that are found to have violated Google’s terms will be removed between now and the end of June. Additionally, extensions will be more closely reviewed prior to being added to the store to ensure that they meet the guidelines. The tech giant suggests that all users monitor their computers’ CPU usage to determine if it’s higher than normal, and report any suspicious activity to Google.