BuddyPress.org

Ok, this worked for me (I hope it fixes evrybody else):

Go to Settings -> Miscellaneous Settings

Set “Store uploads in this folder” to “wp-content/uploads”.

Set “Full URL path to files” to the REAL FULL PATH of your uploads.

Then change bp-core-avatars.php line 389:

Replace:

if ( !$path = get_option( ‘upload_path’ ) )

$path = WP_CONTENT_DIR . ‘/uploads’;

With:

if ( !$path = get_option( ‘upload_path’ ) )

$path = WP_CONTENT_DIR . ‘/uploads’;

else $path = ABSPATH . $path;

It fixes the problem.

Source: https://buddypress.org/forums/topic/avatar-upload-issues/page/2