is there a fix for "vehicle design unavailable, ride performance may be affected" message?

[sweetnovabee]

I have this message on so many of the rides on my game, I'll attach a screenshot to show an example. 

Would love to know what this means / what causes it / how to fix it.

I use the Steam RCT1 (Deluxe) & RCT2 (Triple Thrill Pack), and have tons of downloaded custom made content... but I'm pretty sure all of the rides that display this message are the ones titled like "u(0489)" for example. 

Any help or guidance is greatly appreciated. Thanks in advance!!

[Gymnasiast]

This message appears when the design was created with a type of train that is not available in the scenario you’re playing. This is not a big problem, as it will just use one that _is_ available instead, but this train may behave a little bit differently. It may be lighter or heavier, which may affect how fast it goes, and whether it even makes a hill or not.

In the case of the u(...) designs, those are all from RCT1 and so use RCT1 vehicles. You’re probably playing a scenario that wasn’t from RCT1, so this is expected and nothing to worry about.