In Lightroom Classic, after you upgrade to Windows 10 you get the error 'Unexpected error opening catalog' when you try to open a catalog.

Solutions

Solution 1: Install the Microsoft Visual C++ Redistributable 2012

• For instructions, see: Error in MSVCR110.dll opening apps in Windows 10

Solution 2: Run Lightroom Classic as an Administrator.

1. Open the Program Files/Adobe/Adobe Lightroom folder.
2. Right-click on the Lightroom.exe file.
3. Choose Run as administrator.

Solution 3: Change the permissions on your catalog's folder.

1. Select the folder your catalog is in. By default, this is your Pictures/Lightroom folder. 
2. Right-click on that folder. 
3. Choose Properties > Security > Edit.
4. Select your user name in the Group or user names section. and click Full Control under Permissions. 
5. Click Apply, then click OK out of all the dialog boxes.