I seem to have the same problem on a 7.5.4.2 system and this thread doesn't seem to have any resolution to the problem.

I am dead in the water until i can add a new forum. Could someone please post a reply with a workaround, or bug fix, or whatever?

here are my symptoms:

I became a forum admin on an old pre-existing forum with 40 or 50 existing forums in 5 pre-existing categories. I wanted to add several new forums in a new category.

First, the problem seems to affect both the listing of forums and the listing of categories. Just as a new forum doesn't show up in the forum list pull-downs, a new category does not show up either,

In the forum "control panel -> forums -> forum settings" I see the list of existing forums that had been set up some time ago by others. They go up to number 84 and those 84 seem to operate properly. I click the "Add New Forum" at the bottom and start to fill in. My first clue that something was wrong is that I had created a new category and the new category didn't show up with the other pre-existing ones in the "parent" field. Oh Well, I picked some inappropriate existing category/sub-forum as the parent and kept going.

The newly created forum does not show up in the control panels list of all forums. Thus it cannot be edited or permissions changed. It cannot be used to house sub-forums because it isn't in the pull-down menu of parent forums when creating a new forum.

I did find that by copying the URL for editing one of the pre-existing forums; say number 84, and then changing the board-84 to a board=90 I can get to the edit window for the forum.

I used the SQL window to look at the database with "Select * from ubb_forums;" and the new forum appears to be in the table of forums with correct-looking values.

The new forum shows up in the user's list of forums. It can be clicked and entered. One odd thing that I noted is that the "path" through the forum hierarchy at the top of the forum has a glitch.
Normally the path looks like (with some fake shortened names for space here...)
"TOP >> NEXT >> DEEPER >> ThisForum"
In the case of the disappearing forum this path is messed up. It looks like
"TOP >> NEXT >> DEEPER >> >> ThisForum
And while TOP, NEXT, etc are clicakble links to that forum level, "ThisForum" has lost its clickability.
Looking at the generated HTML for the page, I see
Code
<a href="http://www.EXAMPLEFORUMS.org/forum">TOP</a>
 &raquo;
<a href="/forum/ubbthreads.php?ubb=cfrm">NEXT</a>
 &raquo;
<a href="/forum/ubbthreads.php?ubb=cfrm&amp;c=6">DEEPER</a>
 &raquo;
<a href="/forum/ubbthreads.php?ubb=postlist&amp;Board=90&amp;page=1"></a>
 &raquo;
ThisForum
Note how the name has moved outside the link tags in the HTML and the extra RAQUO quote is added.
The board number is 90. I have played with a few forums. Board 84 is the last correctly operating original forums.

Pressing on trying to screw things up, I went into the SQL command window of the control panel's database tools and did an alter of the record for board 90 poking in the new category number as the parent category. The new category and the new forum contained within now show up in the user forum listing, but when clicked the path is also misisng the new category name and has "TOP >> NEXT >> >> >> ThisForum" as the path with both the category name missing and the forum name still moved outside the RAQUOs. Also, although the new category now shows up in the user's forum list, it is still ommitted from the control panel's list of possibilities when selecting the parent for a new forum.

As there was little follow-up to this thread, I assume that Shawn got his problem fixed.
Can anyone pass on the workarounds?

Thanks loads
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