"都差不多. 找不着 is more used by noutherners.. here give you a new word '找不着北' . it means get lost ^^" This answer is worth reference. As a Shanghainese, I say 找不到 much more frequently than 找不着 But my classmates from the north prefer 找不着. Trust me, no one will care about the differrence.

找不到 = I can't find it ( am not searching for it anymore) 找不着 = I can't find it ( but maybe i am still searching for it) I usually use 找不到. I seldom use 找不着.

They mean almost the same ,but are expressed in different ways. 找不到 means can't find "找不着 means be unable to find. As you see in English they mean almost the same and could be interchanged.

they mean the same thing but I think 找不着 is more frequently used in spoken language. at least i do.

这两个词没有什么差别其实。 可以替换