Ok I know its an old question, but the answer i found didnt help - been running sambapos for 3.5 years - I’m a very small country town cafe - my Pos PC is now running very very slow the SDF file is around 270.000 with clean install its been heaps quicker. I have tried to reset data but SQL/SDF stuff is beyond me - all the SDF viewers I tried cant do anything to help they just hang - so i decided to do clean install and re-set it all up (needed maintenance anyway) but for some reason I now get “can’t save because Sale Transaction used by a Ticket Type” every time i try and add the Australian GST - I’ve search everywhere, what is causing it? as far as i can see its identical to the previous larger SDF setup (yes i backed it up)
thanks in advance
Best thing you can do is stop using crappy CE and install SQL express and use SQL. CE is a horrible option for POS.
You need to create a separate Transaction Type to use for your Tax Templates.
You cannot use the Sale Transaction Tx Type because as it is telling you, it is already in use, assigned to a Ticket Type.
There are different ways to set up the Tax Transaction Type, but most prefer to configure it to use it’s own Account.
So first we create an Account for Taxes …
Then we can create the Transaction Type for Taxes …
And finally, we choose our Tax Transaction Type in the Tax Template …
kendash sorry I have no idea what a CE is and I do have SQL express but have no idea about it.
QMckay thank you so much it worked fine - problem 1 solved 
Using SQL Express will aleviate the size issues you have with CE. If your using an SDF file that means your using Compact Edition and CE is not very efficient and prone to slowdown.
Here is a good tutorial.