Answers.Body: <p>This was apparently caused by an <em>almost</em> complete but failed deployment of the <code>app</code> folder. Only a few files were missing/corrupted so Craft still worked other than the issue described. </p>
  
  <p>I replaced the entire <code>craft/app</code> folder (deleted it, unzipped Craft on the server and used <code>mv</code>) and updated the permissions. At this point I got the same error. The error continued to show up after disabling all plugins other than Commerce. But when I disabled Commerce I was able to check for updates again (Craft was already up to date), and under the limited user the errors no longer appear. Oddly, re-enabling Commerce changes nothing. I did encounter a PHP error when navigating within Commerce, so I followed similar steps to upload a fresh copy. Everything appears to be working correctly now.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-08-01T23:39:28.383Z
Answers.LastActivityDate: 2016-08-01T23:39:28.383Z
Answers.UserDisplayName: Todd Prouty
Body: <p>I have a user group called Content Loaders with limited permissions. After creating a test user in this group I got an "An unknown error occurred" message every time I navigated anywhere in the CP or saved a change (though both were successful). I started adding back permissions and when I re-enabled <em>General > Perform Craft CMS and plugin updates</em>, the errors went away. Not sure if this is a configuration issue on this new staging server, but everything else seems to be working. I can't find any posts about similar issues. Obviously I don't want people doing data entry to be able to perform Craft updates! ;) Anyone have a clue what might be causing this?</p>
  
  <p>Possibly related: even with an admin account checking for updates just shows the spinner image endlessly. I have no problem checking for updates on my local install. This is running on DigitalOcean (with ServerPilot), Ubuntu 14.04.4 x64 with PHP 7.</p>
  
  <p>The only errors I saw in craft.log (which I cleared before doing something that caused the cpanel error to appear) looked like this: </p>
  
  <p><code>2016/07/31 03:45:43 [error] [php] include([snipped path]craft/plugins/commerce/vendor/composer/../guzzle/guzzle/src/Guzzle/Http/Client.php): failed to open stream: No such file or directory ([snipped path]craft/app/vendor/composer/ClassLoader.php:412)</code></p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-08-01T03:55:31.520Z
Comments.Text: This feels like one of three things... (1) a bug in Craft, (2) a corrupt or incomplete `app` folder, or (3) interference from a plugin. I'd start by replacing the entire `craft/app` folder with a fresh copy. If that doesn't work, which plugins are you currently using in your site?
Comments.UserDisplayName: Lindsey D
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-08-01T04:51:31.623Z
Comments.Text: +1 for @LindseyD's #2 guess. Sounds like a file (or multiple) didn't get uploaded/deployed correctly.
Comments.UserDisplayName: Brad Bell
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-08-01T06:16:37.500Z
Comments.Text: @LindseyD You're right! The `craft` folder transfer was incomplete but somehow the install still worked. I replaced the entire `craft/app` folder (unzipped Craft on the server and used `mv`) and updated the permissions. Same error. Also after disabling all plugins other than Commerce. But when I disabled Commerce I was able to check for updates again (already up to date), and under the limited user the errors no longer appear. Oddly, re-enabling plugins changes nothing. Seems okay now (no `[error]` in log), but do you think I should do a complete reinstall to be safe?
Comments.UserDisplayName: Todd Prouty
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-08-01T20:41:10.487Z
Comments.Text: @ToddProuty Just re-uploaded the `app` folder should be good enough.  Would you mind adding your solution as an official answer to this question?
Comments.UserDisplayName: Brad Bell
Tags: <control-panel><server>
Title: "Unknown error" constantly, seems tied to user preferences
ThreadText: # "Unknown error" constantly, seems tied to user preferences
  
  (Asked by: username_0 on 2016-08-01)
  
  I have a user group called Content Loaders with limited permissions. After creating a test user in this group I got an "An unknown error occurred" message every time I navigated anywhere in the CP or saved a change (though both were successful). I started adding back permissions and when I re-enabled *General > Perform Craft CMS and plugin updates*, the errors went away. Not sure if this is a configuration issue on this new staging server, but everything else seems to be working. I can't find any posts about similar issues. Obviously I don't want people doing data entry to be able to perform Craft updates! ;) Anyone have a clue what might be causing this?
  
  Possibly related: even with an admin account checking for updates just shows the spinner image endlessly. I have no problem checking for updates on my local install. This is running on DigitalOcean (with ServerPilot), Ubuntu 14.04.4 x64 with PHP 7.
  
  The only errors I saw in craft.log (which I cleared before doing something that caused the cpanel error to appear) looked like this:
  
  `2016/07/31 03:45:43 [error] [php] include([snipped path]craft/plugins/commerce/vendor/composer/../guzzle/guzzle/src/Guzzle/Http/Client.php): failed to open stream: No such file or directory ([snipped path]craft/app/vendor/composer/ClassLoader.php:412)`
  
  **Tags:** control-panel, server
  
  > **Comments:**
  > **username_1**: This feels like one of three things... (1) a bug in Craft, (2) a corrupt or incomplete `app` folder, or (3) interference from a plugin. I'd start by replacing the entire `craft/app` folder with a fresh copy. If that doesn't work, which plugins are you currently using in your site?  
  > **username_2**: +1 for @username_1's #2 guess. Sounds like a file (or multiple) didn't get uploaded/deployed correctly.  
  > **username_0**: @username_1 You're right! The `craft` folder transfer was incomplete but somehow the install still worked. I replaced the entire `craft/app` folder (unzipped Craft on the server and used `mv`) and updated the permissions. Same error. Also after disabling all plugins other than Commerce. But when I disabled Commerce I was able to check for updates again (already up to date), and under the limited user the errors no longer appear. Oddly, re-enabling plugins changes nothing. Seems okay now (no `[error]` in log), but do you think I should do a complete reinstall to be safe?  
  > **username_2**: @username_0 Just re-uploaded the `app` folder should be good enough.  Would you mind adding your solution as an official answer to this question?  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2016-08-01. Score: 1 | Accepted answer
  
  This was apparently caused by an *almost* complete but failed deployment of the `app` folder. Only a few files were missing/corrupted so Craft still worked other than the issue described.
  
  I replaced the entire `craft/app` folder (deleted it, unzipped Craft on the server and used `mv`) and updated the permissions. At this point I got the same error. The error continued to show up after disabling all plugins other than Commerce. But when I disabled Commerce I was able to check for updates again (Craft was already up to date), and under the limited user the errors no longer appear. Oddly, re-enabling Commerce changes nothing. I did encounter a PHP error when navigating within Commerce, so I followed similar steps to upload a fresh copy. Everything appears to be working correctly now.
  
  
  ---
  
  