This is not the correct workflow for what you want to accomplish. In LR, you don't "save" the finished photo like in PS. Instead LR don't modify the original and save your edits in its database (the catalog). When you need the final image (to print, to end in a email, etc..) you "Export", asking LR to use the original and the settings to create a resulting image with the caracteristics (file format, dimension, etc...) coresponding to the usage of this image. Note that once used, you don't need to keep this resulting image because you can recreate it at any time by doing an Export again. So my suggested workflow would be as follow: Import the RAW in LR, asking LR to store the file on the NAS. Do the edit you want in LR. In LR, right click on the image and select "Edit in" then choose "Photoshop". This will ask LR to call PS and give it the image with all the LR edits. If your original is a RAW, LR will ask for the format to use and create a copy that will be passed to PS. Do your edits in PS. Once finished, click "Save" in PS. This will update the copy passed by LR to PS and these changes will automatically reflected in LR.
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