Body: <p>So I got the error &quot;Heads up! Couldn't open this project&quot; and did research and found out that it is a generic error, then looked up the exact error on this site: <a href="https://legoapptools.azurewebsites.net" rel="nofollow noreferrer">https://legoapptools.azurewebsites.net</a> it showed me this error:</p>
  <pre><code>#WARNLONESTK1 Lonely stack ev3move_rotation-wheel()
  #WARNLONESTK1 Lonely stack procedures_call()
  #WARNLONESTK1 Lonely stack ev3sound_playSoundUntilDone()
  </code></pre>
  <p>I understand that the problem is that I have Blocks floating in my project, but I don't know how to fix it. Here is a link to the project file: <a href="https://www.dropbox.com/scl/fi/aqsg90fv7mptqmi1o5zhc/WRO2024-1.lmsp?rlkey=nd6j1b8dlcrt45iadyqy5ri2d&amp;dl=0" rel="nofollow noreferrer">https://www.dropbox.com/scl/fi/aqsg90fv7mptqmi1o5zhc/WRO2024-1.lmsp?rlkey=nd6j1b8dlcrt45iadyqy5ri2d&amp;dl=0</a></p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-03-23T17:35:39.083Z
Comments.Text: The Lonely stack is not an error. This particular file contains a null value in a list which isn't valid. I updated my answer at https://bricks.stackexchange.com/a/16945/3498 to describe how to fix this.
Comments.UserDisplayName: David Lechner
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-03-23T17:39:16.860Z
Comments.Text: Here is a link to the repaired file [WRO2024 1 - fixed.lmsp](https://1drv.ms/u/s!ApX9UuctkzDD9V9xz67m2HPGcgnQ?e=wYeTkm).
Comments.UserDisplayName: David Lechner
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-03-26T10:38:10.363Z
Comments.Text: @DavidLechner thank you very much I saw you're answer to the other post but I couldn’t solve it on my own. You are a life saver! I hope they will add an easier solution to this. Greetings Jonathan
Comments.UserDisplayName: Joni
Tags: <ev3><repair>
Title: How to fix this Error in EV3 Classroom?
UserDisplayName: Joni
ThreadText: # How to fix this Error in EV3 Classroom?
  
  (Asked by: username_0 on 2024-03-17)
  
  So I got the error "Heads up! Couldn't open this project" and did research and found out that it is a generic error, then looked up the exact error on this site: <https://legoapptools.azurewebsites.net> it showed me this error:
  
  ```
  #WARNLONESTK1 Lonely stack ev3move_rotation-wheel()
  #WARNLONESTK1 Lonely stack procedures_call()
  #WARNLONESTK1 Lonely stack ev3sound_playSoundUntilDone()
  
  ```
  
  I understand that the problem is that I have Blocks floating in my project, but I don't know how to fix it. Here is a link to the project file: <https://www.dropbox.com/scl/fi/aqsg90fv7mptqmi1o5zhc/WRO2024-1.lmsp?rlkey=nd6j1b8dlcrt45iadyqy5ri2d&dl=0>
  
  **Tags:** ev3, repair
  
  > **Comments:**
  > **username_1**: The Lonely stack is not an error. This particular file contains a null value in a list which isn't valid. I updated my answer at https://bricks.stackexchange.com/a/16945/3498 to describe how to fix this.  
  > **username_1**: Here is a link to the repaired file [WRO2024 1 - fixed.lmsp](https://1drv.ms/u/s!ApX9UuctkzDD9V9xz67m2HPGcgnQ?e=wYeTkm).  
  > **username_0**: @username_1 thank you very much I saw you're answer to the other post but I couldn’t solve it on my own. You are a life saver! I hope they will add an easier solution to this. Greetings Jonathan  
  
  ---
  
  ## 0 answers
  
  