Selecting a file from open panel still throws user consent alert

It would help if you were more specific about the code you wrote, the directory you chose the file from, and the error you got. Failing that, I wrote a small test project to exercise this case. The code is pasted in at the end.

When I ran this on 10.15 and choose a file from the desktop, it’s able to successfully copy it. I ran this outside of Xcode, just to make sure the debugger wasn’t affecting things. In Console I saw two log entries:

default
02:15:27.629730-0700
Test125301
QQQ will copy /Users/quinn/Desktop/tmp.txt to /var/folders/ks/l3tlbq5x5gj6ycrwg6sv81jc0000gp/T/Test125301-300323C6-2DEE-4D19-8662-31FA68AD0343/tmp.txt

default
02:15:27.729106-0700
Test125301
QQQ did copy /Users/quinn/Desktop/tmp.txt to /var/folders/ks/l3tlbq5x5gj6ycrwg6sv81jc0000gp/T/Test125301-300323C6-2DEE-4D19-8662-31FA68AD0343/tmp.txt

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

@IBAction func testAction(_ sender: Any) {
    let panel = NSOpenPanel()
    panel.beginSheetModal(for: self.window) { response in
        if response == .OK {
            let sourceURL = panel.url!
            let fm = FileManager.default
            let tmpDir = fm.temporaryDirectory
            let targetDir = tmpDir.appendingPathComponent("Test125301-\(UUID().uuidString)")
            let targetURL = targetDir.appendingPathComponent(sourceURL.lastPathComponent)
            do {
                NSLog("QQQ will copy %@ to %@", sourceURL.path, targetURL.path)
                try fm.createDirectory(at: targetDir, withIntermediateDirectories: false, attributes: nil)
                try fm.copyItem(at: sourceURL, to: targetURL)
                NSLog("QQQ did copy %@ to %@", sourceURL.path, targetURL.path)
            } catch {
                NSLog("QQQ something failed, error: %@", "\(error)")
            }
        }
    }
}