Regardless of whether you work with Windows or macOS, it is always frustrating to see a numerical error code such as error “4302” as some macOS users recently have when they open the Photos app on their Macs.
In fact, some readers have seen this code when copying from Photos on your Mac it says it can’t open the ‘Photo Library’. By contrast, others have seen it when they have certain slowdowns with Photos or see blurry previews.
In most cases, the answer seems to be that macOS 11 Big Sur is not compatible, or at least not fully compatible, with a photo library located on an external drive which has been formatted to ensure compatibility with Windows using ExFAT.
You can check if that’s the case by selecting the drive in the Finder and choosing ‘File> Get Info’. In the Format field, you will read ExFAT. Fortunately, the solution appears to be straightforward, although it requires sufficient capacity.
In fact, you will have to reformat the ExFAT disk. Follow these steps:
- Copy everything from the ExFAT drive to another drive and make sure you have everything.
- Launch ‘Disk Utility’ (found under ‘Applications> Utilities’) and select the drive in the sidebar. (If you don’t see the drive, select ‘View> Show all devices’).
- Warning: this step is irreversible. Click ‘Delete’.
- In the dialog that appears, enter a drive name, select APFS from the ‘Format and GUID Partition Map’ menu from the ‘Scheme’ menu.
- Click ‘Delete’. The ‘Disk Utility’ will format and partition the drive and mount it again.
- Now you can copy the previous content from the unit to the new unit.
- Hold down the ‘Option’ key and launch ‘Photos’.
- In the ‘Choose Library’ menu, click on ‘Other Library’ and navigate to your ‘Photo Library’ located on the newly formatted drive. Select that library and click ‘Choose Library’.
Now you should be back to normal.
If this fails, exit Photos and hold down the ‘Command-Option’ key while launching Photos. Click ‘Repair’ when prompted. This may take some time.
If this also fails, you may have a corrupted or damaged photo library that cannot be recovered, but you can still recover media that was not originally modified.