Check that the auth_user_module and authz_group_module are both loaded. If they are not listed add the following to your httpd.conf , otherwise you will see this error: configuration error: couldn't check access. No groups file?

#Added so "require valid-user" works
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule authz_owner_module modules/mod_authz_owner.so

Create an htdigest file:

$ htdigest -c .htdigest "Restricted" testuser
Adding password for testuser in realm Restricted.
New password: 
Re-type new password:

Example digest config which be placed within your vhost config:

<Directory /var/www/examle.com/files>
  AuthType Digest
  AuthName "Restricted"
  #In some versions of Apache the directive AuthDigestFile is used instead of AuthUserFile got digest auth
  AuthUserFile conf/.htdigest
  Require valid-user
  AuthDigestDomain /files/ 
</Directory>

See Also

http://www.linuxsecurity.com/content/view/133913/171/ Apache, Subversion and "configuration error: couldn't check access. No groups file?:"

Category:Linux Category:Web