The last treasure you found before unlocking "Treasure Trove"

[Asuren]

I had more trouble than I thought on this completion achievement. I went through every zone 3-4 times, using the guide after my 1st run through on my own. Finally i started looking up the video guide on youtube for zones that had pick-up items and compared with what I did. Finally, after about 16 hours of trying to do it on my own, I saw the video guide for Ipsilon Mountain Hut and watched him flick a switch on in the lower floor by the door, to light up a blinking Search Glasses. I didn't recognize it and realized I misinturperated the written guide, thinking I got both items from the top floor light. Walked past it a zillion times. Facepalm.

[Vault Lad]

So, if you're reading this thread in 2012 or beyond I'll just go and assume your at your wits end regarding this achievement. I know that's how I found my way here...I went through all the usual suspects. The Burning Cave, Meia Family Art House, The Crimson Forest, The Underwater sections, everything.

I marked off everything no less, or so I thought. My final treasure was in Tosca Village of all places. It was the chest up the ladder to the north of the village. How in the name of God did I miss this you ask? Well, it's embarrassingly simple.

While doing the Kelolon statue mini-game. I stumbled upon the chest. I took mental note of it, with the clock ticking, I decided I'd finish finding the statues first and get it later. That "later" came 89 hours later after tearing my hair out trying to figure out what I missed.

The achievement isn't glitched. That's all I can tell you. Getting solid advice for this achievement is almost impossible, it will be totally anecdotal and loosely related to your own experiences. Don't. Give. Up. You missed maybe 1 or 2 items, that's all. It can be a seed at the bottom of the ocean or you can have a momentary lapse of judgement like me. But you will get it eventually.

[rm2k3guy]

Two Mother Nature's Spirits in Terrace Cave, still no idea how I missed it.

[Razzazzika]

Ugh, I missed a 500g treasure chest in Tosca At least I only had to retrace 2 discs worth of content.

[Qonok]

I was using a guide and my last was a treasure hunt in Temple of Enlightenment for the Phoenix Ring and Phoenix Discus.
I was so happy to get it there thinking that I must have missed something since I found two other chests I missed while looking for the two Seeds that I missed earlier.

[Nei Debrusc]

I had to backtrack, but I found the four I was missing at the end:

Gold from the Tosla Village (up the ladder, on the way to the northern exit)
Elixer (Black Cave, across the poison, to the east)
Bought one from the auction house (from the Aurora Train)

*5 Life-stealing Tooth(s)* Back Alley of Uhra

[Married2Mary]

I finally have this achievement after backtracking maybe for like 10 items or so..and the last one i found was in cooke and mack's house the pot that is hidden off to the side somwhere.

It seems like most people miss the same items..The ones that i can think of off hand that i had to go back for is

Power Drink-Burning Cave

Mana Herb-Grand Staff Construction Base-Exterior

Tosca Village-Exterior-Pot-500G

City Of Gohtza-Abandoned Apartment-10th Floor-Grounda Bomb

Back Alley-Uhra-Near Castle-Smelling Salts-Metal Pillar

There was a few more that i picked up in the auction house also.

Just wanted to tell people don't give up and follow Achiever(TT guide on here) and Split's Video Guide to a T even if you think you got everything in a certain area.

Good luck everyone!

[Bachlott]

Embarrassingly enough. The last two items I found were from early in the game.

The helmet stuck in the lift in Uhra and the chest in the same area from doing the little lift puzzle.

Been looking for the last things off and on for years now. Sooooo glad to be done with it.

[Elekid]

I started a New Game Plus after a 3 year hiatus from the game thanks to this achievement. I never knew I could hold a grudge for that long. Anyway, if all goes according as planned per SplitPlaythru's videos on youtube, the Phoenix Discus & Ring will be the last item(s) that will unlock the achievement for me. Come hell or high water, I will obtain this achievement.

[Silvanost]

I missed three items after I did the Temple of Enlightenment!

A pot in Numara:
A closet in the City of Saman:
and the final item I missed was a poster at Grand Staff Construction base!

Thank-goodness I got this achievement!