project_service_aprx_object.save() Error from Pro 2.8.x to 2.9 upgrade

[Min-DongChang]

I have a code that a developer created that no long works for me.  With a recent upgrade from 2.8.x to 2.9, the script no errors out at a line " project_service_aprx_object.save()".  What I believe the code is trying to do update the source of feature layers in a map ("1_Service_Status_On").  However, when it comes to the  project_service_aprx_object.save() line, it gives me the following error:

Traceback (most recent call last):
File "<string>", line 686, in <module>
File "A:\Program Files\ArcGIS\Pro\Resources\ArcPy\arcpy\_mp.py", line 285, in save
return convertArcObjectToPythonObject(self._arc_object.save(*gp_fixargs((), True)))
OSError: G:\SDE_User_Connections\Projects\UnitedStates\US_Test01\Web_Services\Test01_Project_Services.aprx

I'm running the code in an empty APRX file so I don't even have the Test01_Project_Services.aprx open.  I'm a novice at python so any I can provide more of the code if necessary.

[RahulGupta2]

I encountered the same problem. To resolve the issue I used the following code.

#Remove existing layer from original template
Original_Template = r"C:\TempScript\original.aprx"
aprx = arcpy.mp.ArcGISProject(Original_Template)
aprxMap = aprx.listMaps("Map")
for lyr in aprxMap[0].listLayers():
      aprxMap[0].removeLayer(lyr)

#Add new layer to original template
_layer = arcpy.MakeFeatureLayer_management(fc,"LayerName").getOutput(0)
aprxMap[0].addLayer(_layer,"BOTTOM")
aprx.saveACopy(r"C:\TempScript\Temp_Template.aprx")

#Save original template to the temp template as aprx.save() is not working
aprx_tmp = arcpy.mp.ArcGISProject(r"C:\TempScript\Temp_Template.aprx")
aprxMap_tmp = aprx_tmp.listMaps("Map")
m = aprxMap_tmp[0]
sddraft = m.getWebLayerSharingDraft("FEDERATED_SERVER", "MAP_IMAGE", "LayerName")

Regards

Rahul

[VincentLantaca · Accepted solution]

seems like there are still issues with aprx.save() even in 3.1, I can run a geoprocessing script with modifies then saves an .aprx file once after opening ArcGIS Pro, but the same script a second time will give the OSError until I re-open Pro

[ASw93]

Can confirm I am seeing this same error still in 3.1. 

[JaredPilbeam2]

Still happening in 3.3.

[TaylorCarnell1]

This happens when rerunning a script because you are getting a new reference to the project and subsequent references are read only. 
It isn't desirable, but is technically documented behaviour. As per ArcGISProject:

Projects can be referenced multiple times, but only the first reference can be saved directly because the other references will be opened as read-only.

You can solve this using:

try:
    project
except NameError:
    project = arcpy.mp.ArcGISProject(project_path)

If you already have multiple references, your memory will need to be cleared first (kernel or machine restart), before this will help.

It's still possible to get orphaned references in certain conditions, so this isn't bullet proof.

[GISDepartmentMFM]

Is there a way to do this without the data redundancy of that comes from save a copy? This feels undesirable if you have a large project.