It took me a while to find the problems in a few .kex files - absolute links to C:\... again. I found them because I got errors on RF's main screen while selecting/opening the imported aircraft. Got "can't find (filename)" error messages at the bottom of the screen after I deleted the oldest versions of RF because I never used them anymore. The error messages disappeared too fast to read them. And the text color of the messages kinda disappeared into the background. If I remember correctly, green text on a green grass background is a little hard to read. I had to edit the error message timeout and forground/background error text colors for my old eyes to actually read and understand the messages. And it was a PITA, because they loaded fine while the RF2,3,&5 directories still existed. I decided to keep only the last 2 versions of RF on my PC, so when I deleted the old RF directories, it broke both the RF7 & RF8 custom aircraft.
Again, that's part of the reason I haven't upgraded to RF9 or EVO. it's too darn messy trying to convert all the custom aircraft into a new version. And it's at least as messy to try to re-import them from the original .rfx files again. If I can do it manually using notepad's find/replace function, I find it hard to believe that a competent programmer couldn't develop a procedure to automatically copy all the custom vehicle files & convert all those absolute links to point to the new version for all the custom content in one procedure. All the affected files are in subdirectories under the vehicles subdir. But it wouldn't be necessary at all if the files contained ".\" or "..\" relative file links instead of the fully qualified "C:\Users\Bill\Documents\RealFlight 8\Vehicles\CustomModels\(some aircraft)\" file links.
Using the .bse files as an example, I load (some aircraft).bse into notepad, do a global Find "Realflight 7" Replace with "RealFlight 8" and save the file. Open a different bse file, repeat for all custom aircraft. Then I have to do it again (and again, and again) for all the colorschemes, etc. for each custom aircraft. Mindless, boring repetition that would be an ideal use of a PC's processing power. It takes hours to do it manually for 40+ aircraft. And would take many more hours if notepad didn't remember the last used find & replace strings. My PC could probably do it in seconds, not hours.