Problem installing the Rezurrection DLC Map Pack (help needed)

[Zak TM]

for some reason i bought the rezurrection dlc pack for black ops 1 and started to install, it begins to install and after a minute or two it says it ready to play. however when i right click properties on my call of duty black ops it says under dlc "not installed". after a couple of times trying to re-install the dlc it finally installed correctly and worked for me. now just today i got the rezurrection pack for my friend and gifted it to him via steam and the same issue. it will install like normal for about a minute or two and say its installed and ready to play but it's not installed at all. tried telling my friend to verify the game cache and to try and re-install the dlc but the problem still persists, is there anyway to fix this issue without re-installing the game entirely? any help would be appreciated :)

[Laptop]

Verify the game cache.

[Zak TM]

i got the problem fixed (not from verifying the game cache) just tried to keep installing and it eventually worked and downloaded. it's possible this map pack may have a weird download bug.