The “An unexpected error occurred while loading this library” error with the Plex Media Player usually occurs when users try to browse a particular section of the library on the Plex Web. This problem is reported to occur mostly on Windows computers.

Optimizing the Plex database

While this fix seems too complicated to do on paper, Plex seems to have done a pretty decent job in this regard. You can easily optimize the Plex service database right from the site. You can find all the instructions you need here:

Use administrative privileges

In some cases, the Plex server may not have the necessary administrator rights. Consequently, due to lack of desired permissions, this error may also occur. In this case, you must have the necessary administrator rights before you can access the service. You need to do the following:

Update your metadata

Metadata issues can also cause various Plex problems, including library errors. Perform a metadata update for the affected partition.

Delete information about other accounts

Some users have reported that they noticed that this problem was caused by a user account information conflict. This can happen if you used different accounts to access the server at the same time.

In either case, the server is logged into one account and the web application is logged into a different account. Deleting the information from the old account should help.

First, log out of Plex, then follow the steps below.

Deactivate Adblock Plus / uBlock

If your browser has Adblock Plus or uBlocks plugins installed (Chrome or Firefox), it may conflict with the Plex server that you host locally. If your situation is similar, you can solve the problem by disabling the plugin when using Plex services.

Several affected users have confirmed that the “An unexpected error occurred while loading this library” error will no longer occur after deactivating the Adblock Plus or uBlock plugin.

To disable adblock extensions in Chrome, type “chrome: // extensions /” in the navigation bar and press Enter to open the “Extensions” tab. Inside, scroll through the list of installed extensions and disable switching between AdBlock and uBlock extensions.