Has the AdBlock button vanished from the browser toolbar every time you open Chrome? Visit chrome://extensions and see whether AdBlock has been disabled or even uninstalled. Either way, it could be an issue with malware, an extension that doesn't like AdBlock, a broken installation of AdBlock, or even Chrome itself.
Malware
If AdBlock is constantly being uninstalled or disabled every time you open Chrome, it could mean your computer is infected with malware. Malware often looks for and uninstalls extensions that can keep them from doing their nefarious work.
The first thing you should do is check chrome://extensions for any extensions you don't remember installing yourself. If you find any, remove them. Next, take the necessary steps to remove malware from your device.
Extensions
Sometimes browser extensions don't play well together, so one will disable the other. Here's how to check for that issue:
- Reinstall AdBlock
- Disable all other extensions except for AdBlock
- Restart Chrome a few times. If AdBlock is still there each time, it means one of the extensions you disabled is the culprit.
- Enable each of the other extensions one at a time, restarting Chrome after each one, until AdBlock is uninstalled or disabled again. The last extension you enabled is the one disabling AdBlock.
Reinstall AdBlock
Extensions can become corrupted if something goes wrong in Chrome. One indication of a corrupted extension is that its icon in the Chrome toolbar changes to a jigsaw puzzle piece. Chrome disables corrupted extensions. You can visit chrome://extensions and try to repair a corrupted extension, but it's better just to reinstall it.