If you realise that you have missing inventory, you can try this tip. Follow the steps below as soon as possible:
1. Login to the Preview Grid and find a quiet place where no one will annoy you while you are trying to solve a problem.
Steps to login to the Preview Grid:
Open Second Life client, but do not log in.
At the login window, press Control-Shift-G to bring up the "grid selector" box. Should show 'agni'.
Select "Aditi" from the drop-down box. NOTE: I had to type this in by hand it was not in drop down, but it works.
The menu-bar should turn Red, and the background image will change.
DO NOT REZ ANYTHING WHILE ON THE PREVIEW GRID. GO INTO BUSY MODE IMMEDIATELY. DO NOT ACCEPT ITEMS, DO NOT DELETE ITEMS, DO NOT PASS OR RENAME ITEMS.
2. Open your inventory, type in a search term and allow your inventory to populate.
3. Got your goods back? Brilliant! Quit the viewer, login to the Main Grid (change the grid name in the login window back to Agni) and do the same thing. Once you have retrieved your items on the Main Grid and your inventory has fully populated, logout and cache your inventory.
4. Log back into the Main Grid, recheck inventory. You should find everything has returned to normal. Enjoy your Second Life!
This technique has been proven to work more than half the time so it may save your hide.
Please bear in mind that you should only expect positive results if you attempt this workaround as soon as possible upon discovery of your missing items.
This is NOT a guarantee that you will be able to recover your items but having at least a chance at doing so is much better than no chance at all. I hope this helps some of the Residents that fall victim to this issue.