While playing multiplayer, a map I didn't have was chosen - http://osu.ppy.sh/b/31974
I went to the site and downloaded the map.
I double clicked on the downloaded map.
Osu went to the black screen saing "Importing 7401 - Home Made Kazoku - Shounen Heart (TV Size).osz"
Osu returned to the lobby but still said I didn't have the map and asked me to download it again.
I left the lobby and went to single player mode, it selected the map I had just downloaded and said it needed to be updated.
After I updated the map I rejoined the multiplayer lobby successfully and it acknowledged that I had the correct map.
To try and narrow down the problem:
I deleted the map and downloaded it again.
I joined the same multiplayer lobby (although the game was now in progress)
The song banner now told me that the map needed updating.
Cliicking the song banner updated the beatmap so that it turned green.
Possible diagnosis:
When importing a beatmap in the multiplayer lobby, if it's out of date Osu will ask you to download it rather than update it.
I went to the site and downloaded the map.
I double clicked on the downloaded map.
Osu went to the black screen saing "Importing 7401 - Home Made Kazoku - Shounen Heart (TV Size).osz"
Osu returned to the lobby but still said I didn't have the map and asked me to download it again.
I left the lobby and went to single player mode, it selected the map I had just downloaded and said it needed to be updated.
After I updated the map I rejoined the multiplayer lobby successfully and it acknowledged that I had the correct map.
To try and narrow down the problem:
I deleted the map and downloaded it again.
I joined the same multiplayer lobby (although the game was now in progress)
The song banner now told me that the map needed updating.
Cliicking the song banner updated the beatmap so that it turned green.
Possible diagnosis:
When importing a beatmap in the multiplayer lobby, if it's out of date Osu will ask you to download it rather than update it.