Why Would You Want To Do This
The only time I have had to do this is when someone has inadvertently run the multicurrency wizard and it had changed their default currency for all their inventory items to something other than their default currency. They then turned off multicurrency and all the inventory items had remained in the other currency. You would only follow these steps if a large number of inventory items are in the wrong currency.
As an example
The customer's inventory was all in Canadian Dollars prior to turning on multicurrency. Once they had realized what they had do, they turned the multicurrency back off, but after doing this discovered that it had left all the inventory in US currency.
How To Correct This Issue
The easiest way will be through data load.
Always do a backup before doing a data load.
Always make sure that everyone is out of the system before doing a backup.
If you need an up to date inventory file it can be generated first by running a Stock Count report and export all categories to a csv file. See Wiki Article on Generating The Stock Count Report. http://wiki.wws5.com/doku.php?id=stockcountreport
You can ignore The section on importing into Excel. All we need for this particular issue is to be able to save the count to a CSV. If only a single category or a couple categories are affected, then you could follow the same process, but only generate a stock count report for that category.
Open the Part Load by clicking on Menu - Inventory and Purchases - Data Load - Part Load
opened the inventory file in a data load,by clicking the From File button, select the file, and click next.
in this screen you only need to set the Category and Part Number columns, by selecting the column so it turns yellow, then from the drop down select column, and then select the part number column and select part number from the drop down. Set all others to none, and Click Next
Select “Load into Regular Parts”, and “Update existing Regular Parts and load others into Virtual Warehouse”. Also on this page, set Foreign Currency Code to the currency type that you want to change all your inventory to. This should be available from the drop down.
Now click Next, and Next, then click on load. Click yes to continue with the data load, then OK, and you can view the log to see if all items were updated.