**BUG** Components lost from PCB layout Concise problem statement: All of the components from a PCB layout file are lost when opening the file. Tracks, board outline, added text etc remain. The "Components" list in the Design menu is empty. Steps to reproduce bug: Unsure. It has happened twice today, on the same design. The first time the three components on the bottom side were missing - I guessed I might have removed them by accident, so I re-added them using the "update PCB" command in the schematic viewer, and re-postioned them. Then to double-check I re-ran the "update PCB" command again. This time all of the components were added (top and bottom), outside the PCB footprint. I had to manually re-position all of the components, recreate the gerber files etc. Fortunately I saved the schematic and artwork files locally, as .json files, using the "Easyeda source" command. Then I closed and re-opened the browser and this time ALL of the components were missing, on one of my two projects. I created a new project and imported the saved .json files using the Open EasyEDA file command. The components were present and the "update PCB" command showed the artwork was in sync with the schematics. I think (though I am not certain) that the three components on the bottom of this new project then vanished again. However they are there now. If I was asked to explain this I would speculate that the save of the file to the server did not complete, so when I re-loaded the file I got a truncated file with the components missing. Or similar. Can this happen? Is there integrity checking of files as they move in both directions? Results: Expected results: Browser: Firefox.