Bad presentation mode crash in 5.0.3


    Jun 28 2008 | 4:50 pm
    I had a patch in presentation mode, one object was selected. In the Inspector I unchecked the box "Include in Presentation". Max crashed, the patch was damaged. As I tried to open it Max said:
    Test Preset: bad magic number
    Test Preset: read failed error 0
    I opened the damaged file in BBEdit, code looked ok, pasted it into a new Max patch. Saved/replaced the old file. Did not went well, as I reopened it Max complained about a bad header. Deleted the old file, new patcher, pasted the code and saved as a new file. I am back in the game. Unfortunately I could not reproduce the crash yet.
    What is a magic number?

    • Jun 28 2008 | 5:36 pm
      > I had a patch in presentation mode, one object was selected. In the Inspector I unchecked the box "Include in Presentation". Max crashed
      Do you remember what kind of object you were inspecting? There have been problems in the past with removing objects from a presentation. Perhaps we can track this one down if we know where to look.
      Bad magic number is just a user-unfriendly way of saying the file is corrupted. We should try to make the error message more helpful.
      David Z.
    • Jun 28 2008 | 8:55 pm
      Could you briefly explain what is a corrupt file?
      since the max patches are text file ...
    • Jun 28 2008 | 9:06 pm
      My guess is that the file is supposed to be text but it can't be verified as valid UTF-8. This probably means it has garbage in it somewhere (another way of saying it is corrupt). If it fails the UTF-8 test, then we try to see if it is an old Max binary file, and, not finding the correct header for that type of file, we say it has a bad magic number.
      Another possibility is that the file is fine, but the user has given it the wrong extension, which leads Max to believe it is not a Max 5 JSON format text file. When Max tries to validate it as an old format file, it fails.
      I have personally never seen a seriously corrupt JSON file, so I don't know which of these alternatives is the more likely scenario.
      David Z.
    • Jun 28 2008 | 9:40 pm
      Quote: David Zicarelli wrote on Sat, 28 June 2008 19:36
      ----------------------------------------------------
      > Do you remember what kind of object you were inspecting? There have been problems in the past with removing objects from a presentation. Perhaps we can track this one down if we know where to look.
      ----------------------------------------------------
      I don't remember the object because I just wanted to see if it instantly vanishes from the presentation. But there were only 3 textbuttons, an umenu and a palette as background. One of these objects was it.
    • Jun 29 2008 | 5:34 am
      ----- $B85$N%a%C%;! $B:9=P?M(B: David Zicarelli
      $BAw?.F|;~(B: 2008$BG/(B6$B7n(B29$BF|(B 2:36
      $B7oL>(B: [maxmsp] Re: Bad presentation mode crash in 5.0.3
      > I had a patch in presentation mode, one object was selected. In the Inspector I unchecked the box "Include in Presentation". Max crashed
      Do you remember what kind of object you were inspecting? There have been problems in the past with removing objects from a presentation. Perhaps we can track this one down if we know where to look.
      Bad magic number is just a user-unfriendly way of saying the file is corrupted. We should try to make the error message more helpful.
      David Z.