diff --git a/src/octoprint/printer.py b/src/octoprint/printer.py
index 7b897ee7..e6abdb2d 100644
--- a/src/octoprint/printer.py
+++ b/src/octoprint/printer.py
@@ -546,7 +546,7 @@ class Printer():
 		self._streamingFinishedCallback = streamingFinishedCallback
 
 		self.refreshSdFiles(blocking=True)
-		existingSdFiles = self._comm.getSdFiles()
+		existingSdFiles = map(lambda x: x[0], self._comm.getSdFiles())
 
 		remoteName = util.getDosFilename(filename, existingSdFiles)
 		self._comm.startFileTransfer(absolutePath, filename, remoteName)