Decrypt/verify doesn't ask for passphrase, then decrypt operation fails

I created a key pair yesterday and sent the public key to a colleague. As a test, he sent me a test.txt.gpg file. I haven’t been able to decrypt it. I right-click the file, click “Decrypt and Verify,” leave the default settings (“Create all output files in a single folder”), and then click Decrypt/Verify. The program never asks for my passphrase, and on the Results screen it just says “test.txt.gpg → test.txt: Decryption failed: Decryption failed.” Does anyone know why this is happening?

I have the same problem.
Except I have the following error:
ENCQuoteLineAttributes.tar.gpg - Input to c:\Program Files (x86)/GNU/GnuPG/gpgtar.exe --openpgp --skip-crypto --set-filename …: Decryption failed: No Data

The encrypted file is 10Gb big.

Help anyone?

Please give more information about your system when asking for help.
The version of windows or Gpg4win may make a difference in the behaviour.