Hey @mrylnd 

I've been where you are...many times.

Like most things accounting there is no easy or "right" answer but this should "cure-all" inventory issues

Short answer is "NO" do not mess with your starting values (plus you can't delete/void them) if you have finished/closed any fiscal periods. Simply because it's much harder to fix than and 'unspin' the changes you need to make than the below which focuses all adjustments into one date in quickbooks keeping the changes obvious.

Draw a line in the Sand, figure out what you know for SURE.

1. Pick a Point in Time to start from, usually the previous Year End
2. Agree the List of Items, Qtys and Value on hand at that point
   (FYI This total should agree with the Balance sheet # filed)
3. Use the Quickbooks Items Page to export your Current Items to Excel to help with this

Now let's remove everything so we can control what Quickbooks knows about your Inventory

1. Run an Inventory Valuation Summary at your Fiscal year end & Save/Download it
2. Create a $0 Sales Receipt and "Sell" all your Inventory for $0 on the 1st day of your new Fiscal Year
   (Pro-tip - You can save time and upload this using your Inv report data if you
3. Re-run the Inventory Valuation Summary but change the date to be the 1st day of your new Fiscal Year
   (This Report should now be $0 with 0 Qtys of everything, basically a blank report which means your Inventory is reset to ZERO)
4. Now check your Profit & Loss Report for Day 1 of the new period, you will see a LARGE COGS $number there, compare this to your Inventory Balance sheet account and they should contra each other.
5. Make a Journal to move this value from COGS back to the Inventory Account on your Balance sheet
   (this is optional at this point as you can create it at the end of the last step)

Good to Know

[Using a transaction date of Jan 1st can make it very simple to monitor the changes to your Profit & Loss and Balance sheet reports]

Recap: So far we have:

-Determined what our Inventory "should be"

-Removed the "Trash" from QBO

-Kept our Inventory Balance sheet $ integrity in tact !

Final Step - 'Buy Back' all your Inventory properly

1. Using the List created in Step 1 - ensure Costs, mapped accounts and Quantities are correct
2. Change the Inventory" Qty As-Of Date" to be the 1st day of your new period
3. Upload the new Inventory data to Quickbooks make sure to check the box at the bottom telling quickbooks online to overwrite your existing data
4. This process can take a few attempts and is limited to 1,000 rows of data, best to test it first on a few items or break the list into sections and repeat the process
5. When this is done, check your Profit & Loss again and you'll notice that there's now a large balance in a "Inventory Adjustment" account
6. Like the above, take this balance/amount and journal it back to your Inventory Account on your Balance sheet

I hope this has helped, but I do acknowledge that managing Inventory in Quickbooks online can be tricky unless you are very experienced like we are. If you need follow-up feel free to reach out or reply to this message.

-Richard

MCBB - Bookkeeping and Business Services-ps I wrote this answer without checking QBO too much so I may have glossed over some parts, let me know and I will update the answer, either way a thumbs up would be nice thanks