How do you lock an external hard drive on Windows 10? Can anyone recommend any good, safe programs?

How do you lock an external hard drive on Windows 10?

Please explain what exactly you mean with "lock an external drive".

If you mean "encrypt" then I recommend you check out the links posted by the other respondents.

Note that data encryption is dangerous. In this forum we keep getting posts from people who ask for a safe, crack-proof method to encrypt their data. A few months later they come back here, pleading for help, because they lost their encryption certificate and are unable to open their files. They now wear a different hat. Previously they asked for a crack-proof encryption tool. Now they ask for a method to crack their crack-proof files. Go figure . . .

True.  That's why an unencrypted backup somewhere safe is advised.

Indeed. But lots of people ignore the need to have a backup copy of their files (encrypted or unencrypted) until they suffer a major disaster and come here, begging for help.

I little while ago I replied to a question from a poster who was using BitLocker as a crack-proof encryption tool. He lost the key and got very angry at Microsoft for not having built a back-door into BitLocker. He refused to accept that "crack-proof" and "back-door" are mutually exclusive. If there is a back-door then the encryption is crackable.

If you have Windows 10 Pro you can use BitLocker which is in-built into Windows.

If no Pro:

https://smallbusiness.chron.com/password-protec...

Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.

Bitlocker which is built-in to Windows 10 would be my choice for data encryption.

https://support.microsoft.com/en-us/help/4028713/windows-10-turn-on-device-encryption