Dropbox SDK for iOS works on simulator, not on actual device

Hi again, I did some testing using NSFileManager. I Added this piece of code before downloading the file into the path:

if fileManager.fileExistsAtPath(localPath) {
    println("File exists")
} else {
    println("File does not exist")
}

On the simulator it prints "file exists", but it downloads the file to the desired location anyways, just overwriting the existing file. On my actual device it prints "file exists", but is unable to overwrite.

So i tried this:

if fileManager.fileExistsAtPath(localPath) {
     println("File exists")
     fileManager.removeItemAtPath(localPath, error: nil)
} else {
     println("File does not exist")
}

(This code twice in a row, to check if file was removed successfully)

On simulator i get: File exists, File does not exist.
So again, simulator working as expected.
On iPhone i get: File exists, File exists. -> (so still not able to download the item).