Uploaded gCode Files are disappearing from Upload Directory

I'm saving gcode Files sliced with s3d to a networkfolder uploads on my pi zero w.
I can see the files for some seconds in the OctoPrint File List and also with Explorer in the network folder.
After some seconds the files are disappearing

octoprint.log says

2019-12-29 12:34:06,575 - octoprint.util.comm - INFO - Telling the printer to set the busy interval to our "communicationBusy" timeout - 1s = 2s
2019-12-29 12:37:09,386 - octoprint.filemanager.analysis - INFO - Starting analysis of local:Case_mount.gcode
2019-12-29 12:37:09,425 - octoprint.filemanager.analysis - INFO - Invoking analysis command: /home/pi/oprint/bin/python2 -m octoprint analysis gcode --speed-x=3000 --speed-y=3000 --max-t=10 --throttle=0.0 --throttle-lines=100 /home/pi/.octoprint/uploads/Case_mount.gcode
2019-12-29 12:37:22,918 - octoprint.filemanager.analysis - INFO - Analysis of entry local:Case_mount.gcode finished, needed 13.53s
2019-12-29 12:38:14,575 - octoprint.filemanager.analysis - INFO - Starting analysis of local:Case_mount.gcode

same happend if trying to copy a gcode file to the networkforlder by explorer.
If copying a NOT gcode file e.g. axc.stl the file stays in the networkfolder.

If using OctoPrints WebfrontEnd Upload Button or Drag AndDrop a file, same happens, the file occurs for seconds in the list and than disappers again.

I'm quite new with OctoPrint but yesterday i've installed another Pi ZeroW with OctoPrint with no Problems

2 Hours ago i printed the same file with no Problems.

Only Changes, i installed two plugins Bed Leveling Wizard and Filament Change

new installed, now it works