Chrome extension warns “Cannot load extension with file or directory name Thumbs.db. The filename is illegal.”

Question

Whenever I use \"load unpacked\" to test my custom Chrome extension, I get an error:

There were warnings when trying to install this extension:

Answer 1

As wOxxOm said, there is a thumbs.ds archive inside. If you are using Windows, a ds file can be understood as a protected operational system file. So everything you need to do is go to control panel -> folders options and unmark "hide protected operational system files" or something like this.