okay so ive seen this before during testing happening with someone else on the forums.
please read a few posts here:

https://ludeon.com/forums/index.php?topic=41783.msg422812#msg422812

now, the thing was, it wasn't reproducable for me, bc the person who had this problem, was either not on the current version of the game (it is now 0.19.2009) OR which is more likely, he was using an older save. the moment he started a new game the error and bug were gone.

Okay, thanks for that, it's true that i've been playing my current save-file all the way from the 1.0 unstable testbuild over to the 0.19 unstable testbuild now into the officiall B19 build and never started a new game for like probably 3 weeks now. =D

I just ran into this too. I am using an existing save. I'll reinstall the mod next time a start a new save as see if that's it. I was so confused when all my mountains turned into rugs.

I found this mod today & wanted to integrate it in my new B19 session which Im playing for a couple of days already. Encountering the exact same problem & its a real pity that you can't use it with existing saves apparently. I'll be happy to help though if you're willing to find a solution.

i am working on fixing this already.. it used to be you could add the mod to existing saves no problem

okay so i had a look at it the last few days and I just released an update which *should* fix the bug when adding the mod to a new save (at least it does on my end) pls make sure you have the current update of the mod when trying

Good job!
I did a quick check & can confirm that your mod is now working with an existing save on my part.

Originally posted by Fearchar:

Good job!
I did a quick check & can confirm that your mod is now working with an existing save on my part.

unfortunately...my fix made people with existing saves lose their limestone mountains I rerolled the update

so, if anyone is interested what the actual problem is
It seems that I am extremely unlucky regarding the FLIKFUT defname..there seems to be a hash collision with this exact name and limestone (game basically thinks they are one and the same)
now my options are, fix the bug (change the name) and make new users who add this mod to their game be happy and in the process break everyone elses game bc changing a defname in an existing save is catastrophical...
or keep the bug until 1.0 when everyone is forced to update anyway.
so yeah lol i am opting for door number two

Haha, Life aint easy !
Since I made a new save I thought that might proove as legit now, but it isnt.
Fair enough, prepare for 1.0, thanks for trying !

I can second this experience while using this mod with many others. Only limestone is affected in my experience also although mine wasn't replaced with those 'wooden frames' at any point but by nothing, as in your final screen.

Error was: "MakeThing error: FLIKFUTRug is madeFromStuff but stuff=null. Assigning default."

My second game with this I chose an area with no limestone.

Error was: "Could not load reference to Verse.ThingDef named zLIKFUTRug"

Both errors only occurred on a save after full restart of the game. When removing the mod and loading the save there were errors for all the stuff added by this mod.

Error was: "Could not load reference to Verse.ThingDef named [insert shorthand IKEA product]"

Answer:

"Verse.ThingDef named zLIKFUTRug" was in this list but "Verse.ThingDef named FLIKFUTRug" was not.

Starting to smell like a typo no?

no
i explained what i did and that i reversed it and what was actually wrong and why, above

Originally posted by spoonshortage:

no
i explained what i did and that i reversed it and what was actually wrong and why, above

I did read your most recent replies just now. The problem was recieved in a save I started just today.

Surely "Verse.ThingDef named zLIKFUTRug" != "Verse.ThingDef named FLIKFUTRug"

Edit: I look forward to you getting this sorted as some alternative furniture choices wouldn't go amiss.

ok so. i briefly renamed the defname to zLIKFUT because that got rid of the limestone error for existing saves. BUT i had to reroll and change it back to the normal FLIKFUT bc that change broke peoples saves that were already fine. so if you start a new game with the mod there is no issue like always. only existing saves were affected by this.
I will change the name (and fix the bug) with the next game update, bc then people have to start new games anyway and i can make gamebreaking changes to my mod.
if you started and saved a game during the brief time I had it set to zflikfut your game will now have problems bc it obviously cant find that item (as i changed it back)
and im sorry but there is nothing i can do other than recommending a new game.

I have just looked to check what you were saying and found you had reverted changes to "ThingDef_RustikaFurniture.xml" and steam auto fed them to me around 16:00 GMT. This is a problem with how steam works not necessarily what you've done mate. I see you've fixed the issue for the new version. I'll change it back to zLIKFUT in the mentioned xml.

TIP for others: Backup your "\Steam\steamapps\workshop\content\294100\" folder and before sitting down to rejoin your rimworld delete the contents and extract your backup.

Alternative: Steam offline mode for however long you intend to use your current saves.

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Edit: Great work on A Dog Said...