Disappearing Categories?

OpenCart 1.4.9.3
Default2free theme

I am loving OpenCart more and more, and I am grateful at all the helpful advice here.

I'm having a strange problem with categories on the Admin side. I'm sorry if this has been answered before, but I couldn't find this specific problem.

I've got the following:

CATEGORIES>Category>Sub-Category>Sub-Sub-Category

The final sub-sub-category keeps disappearing from the panel category>product>item>link
It will work for a while, then disappear. If I clear the cache files, it will reappear, but the associated data is gone (i.e., linked files are no longer linked).
It never disappears from the front end as a sub-category, and products still display correctly if they haven't been modified while in "missing subcategory" mode.

If I go into categories and try to add them back in, they will just re-appear.

I appreciate any suggestions.

Very similair problem here...I hope someone looks into it.

Did anyone get to the bottom of this problem? i am having the same problem too and it's really frustrating! spent 2 days putting products back into there categories only to have it do the same thing and about 20% of the products become unlisted, by that i mean they are still in the data base and when i go to Products, click edit, some categories and sub categories are missing from the LINKS section, i put in a new category and instantly they all appear again and i can tick the items putting them back into the right place. I'm assuming that's why items are getting none listed?

Bit of info on my site: www.maidstone-engineering.com opencart version Version 1.4.9.1 I am the owner and i know pretty much nothing about code, so you might have to bear with me a little! we had a developer make a few changes to the site giving us a stock list up datable from excel, and a shop sales section so we could take stock out without shipping for a Till sale in our shop but that didn't seem to affect it and was tested well some time ago and this seems to be a new problem!

I did read posts about missing categories and followed there fixes and that seemed to make the categories disappear all the time but didn't solve the problem.

If anyone could help or has any ideas this would really, really help as this is a large stumbling block for me when i was hoping to stock the shop and go live next week best part of two years of work!

Is there any point in upgrading my version to a newer one, do you think it could solve this problem or would i be opening up a can of worms? any advise muchos appreciated!

Alex

UPDATE: 24AUG 2012

Found a fix in the extensions which fixes the cache file, the extension writer tested and made it work with my version of opencart, put the Vqmod in, added extension, changed the .xml file and hey presto problem fixed!

here is the extension: http://www.opencart.com/index.php?route ... on_id=6815

this bloke was great! hats off to opencart developers going the extra mile!

Alex