
Now that you have a bit of a background on the technical aspect of this system, you may be curious as to why this is happening. What is Causing this ADB Vendor Keys Error? When you grant access, ADB and Fastboot tools will also save your ADB_VENDOR_KEYS to the PC (this is similar to your PC’s RSA key fingerprint). Although, you can set the “always allow” box within the prompt to automate this for future attempts. This only lasts for the current session on this specific PC and will need to be allowed again in the future. If you allow access, your smartphone can then be accessed with ADB and Fastboot tools from this specific PC.

You’re told this PC’s RSA key fingerprint and then given the option to allow access or to deny it. You’ll be asked if you want to allow USB Debugging access from the PC it’s connected to. The prompt may look different depending on what software you’re running, but the general idea is here. USB Debugging Mode Prompt from the Samsung Galaxy Note 10+
