Steps

• Running Jenkins version 2.426.3
• Upgraded Build Blocker Plugin from 1.7.9 to 165.v5ecb_fb_f61520
• Jobs failed to run: pending - Exception evaluating if the gueue can run the task
• From jenkins.log

  2024-05-09 16:15:39.749+0000 [id=115]   WARNING hudson.model.Queue#getCauseOfBlockageForItem: Exception evaluating if the queue can run the task 'Sample-Build-Misc'
  java.lang.ClassNotFoundException: com.cloudbees.hudson.plugins.folder.AbstractFolderPropertyDescriptor
  Caused: java.lang.NoClassDefFoundError: com/cloudbees/hudson/plugins/folder/AbstractFolderPropertyDescriptor
          at hudson.plugins.buildblocker.BuildBlockerQueueTaskDispatcher.getBuildBlockerProperty(BuildBlockerQueueTaskDispatcher.java:220)
          at hudson.plugins.buildblocker.BuildBlockerQueueTaskDispatcher.canRun(BuildBlockerQueueTaskDispatcher.java:95)
          at hudson.model.Queue.getCauseOfBlockageForItem(Queue.java:1209)
          at hudson.model.Queue.maintain(Queue.java:1544)
          at hudson.model.Queue$1.call(Queue.java:332)
          at hudson.model.Queue$1.call(Queue.java:329)
          at jenkins.util.AtmostOneTaskExecutor$1.call(AtmostOneTaskExecutor.java:109)
          at jenkins.util.AtmostOneTaskExecutor$1.call(AtmostOneTaskExecutor.java:99)
          at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:80)
          at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
          at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:121)
          at java.base/java.lang.Thread.run(Thread.java:840)
  

Workaround/Fix

• Installed Folders plugin (6.858.v898218f3609d) and it works