Fatal Error: Unable to communicate with the Project Database Service in AutoCAD Electrical

Issue:

Causes:

• Specific security update (KB4484127 or other) for Microsoft Office 2010 (and newer)
• The project database (MDB) file is corrupt and needs to be deleted (See * item in the Solution section)

Solution:

1. Turn off All Microsoft Office programs as well as all Autodesk programs ( including Autodesk desktop app).
2. From the Control Panel, Add/Remove Programs, click on the View Installed Updates on the left pane.
   
3. Uninstall a Microsoft update named: KB4484127  (Usually under the category: Microsoft Access database engine 2010).
4. Install the more recent Office update available here.
5. Start AutoCAD Electrical again to check whether it works. 
6. If the problem continues, proceed with these additional steps:
   1. Make sure that you have access to the installation package of AutoCAD Electrical. ( If not present, download its installation package from your Autodesk account. manage.autodesk.com)
   2. Turn off All Microsoft Office programs as well as all Autodesk programs ( including Autodesk desktop app).
   3. From the Control Panel, Add/Remove Programs, under the main program uninstall windows, uninstall the product called: Microsoft Access Database Engine 2010.
       
   4. Reboot the computer.
   5. Navigate to the AutoCAD Electrical installation folder (by default under C:\Autodesk).
   6. Under the AutoCAD Electrical installation folder, navigate to the directory (<AutoCAD_Electrical_20xx...Win_64bit_dlm>\3rdParty\x64\AceDataEngine\) and install the application named AceRedist.msi.

After the installation is finished, run AutoCAD Electrical. It should be working now.

C:\users\<username>\AppData\Roaming\Autodesk\AutoCAD Electrical 20xx\Rxx.x\enu\Support\User   (where the Xs denote the Electrical version).

Source:https://knowledge.autodesk.com/support/autocad-electrical/troubleshooting/caas/sfdcarticles/sfdcarticles/Electrical-Unable-to-communicate-with-the-Project-Database-Service.html