I have been having this issue for the past few major updates as well; everytime this happens, the game has the "Install" button in the library of the Plarium Play launcher, and I am forced to entirely redownload and re-install the game.
My PC is brand new (so I doubt my hard drive is dying), I've never touched or moved the game files, and my internet is working fine with everything else (whether it's general browsing, streaming or other games). Redownloading Raid through the Plarium Play client averages at 0.8mbps, when my normal internet speed is 50mbps.
For a game that's heavily focused on time gates and resource refills, it's very disruptive being unable to access the game due to abysmal download speeds and installation times. Would like to know too if there is a fix or workaround for this issue, or if it is at least a currently known issue.
I'm having an even worse issue. Played the game just fine yesterday. Went to launch today and nothing. Launch button is dead. Went to Plarium app to launch from there.... nothing. Said "fine, I will Uninstall and Re-install". Uninstalled app and game with option to keep my setting for re-install. Now the app won't let me re-install the game because it thinks it's already installed after I uninstalled it. It's not even in the Program Files anymore but the app won't let me re-install the game. Guess I'm done here unless anyone has any ideas.....
Finally got to be able to reinstall the Plarium Play app and now it won't launch from my PC. Just a dead link. Click it and nothing. What a joke. "Support" instant messaged me a solution that had nothing to do with my problem. I'm glad I never gave these people any money, and I was considering it. Now, they have no chance in hell of seeing a dime from me. What a terrible app. Can't believe I wasted this long on this crap.