YdestroyerY

Yeah, it's definitely confusing. The CK only usually only allows you use ESMs as masters. But the only real difference (aside from the file extension ".esm") is a flag in the file indicating that it's an ESM. Otherwise they're the same as ESPs. In case you didn't know, the CK lets you select a normal ESP and use its data, but when you try to save your file it doesn't add that ESP as a master to your file. It just ignores it and doesn't say anything. This breaks any references you made. So when you "Esmify" an ESP with Wrye Bash, you're simply changing the flag to say that it's an ESM. This "tricks" the CK into allowing you to save it as a master in your file. After you save your file, you change the flag back and the game handles it without a problem. I forgot to mention another solution. You could always copy all of the records that you're using from KS Hairdos into your own mod. Then you don't need to use it as a master. However, you have to know which records to copy (records can refer to other records, which you'll need to copy as well). Also, you should still get permission from the original mod author if you're going to release it, since you're taking content from the mod. Thank you so mush freind, that was really helpfull, you saved me x)