So, been using trader for about 3 months, about 2 bil buy, 2 bil sell at any one time, approx 4 bil in wallet.

Set it off today, come back an hour later and my wallet is pretty much empty, all sell and buy orders have been changed to have the decimal point in the wrong place (i.e. 444,299,989.00 instead of 4,442,999.89).

Needless to say I've just lost about everything on that character. Thank god I didn't have more in the wallet.

I suggest trying new builds with a different character, you lose a day of trading potentially, but avoid risk of big isk losses. You might also be able to try it on the test server, but that part I haven't verified.

Dont know how it is possible. Trader verifies price change and cancel order if price change is not correct. Many people confirmed this, that trader dont approve order modification if resulting price change is totally wrong. I dont tell that I dont believe you, but to understand anything I need log file. Also as Calser mentioned, it is better to test new builds, at least dont leave unattended. If miners care about hulks and dont risk to run bot w/o attention after eve patches, then what to tell about trader, which operates with much more isks. Ok.

What version did you use? Latest version is 4.1.6 and there is a setting - custom decimal separator available.
If you dont tick checkbox, trader will try to detect decimal separator based on language of the windows used during installation of the windows. You can also redefine decimal separator and use comma or point.

Oh I completely agree, my fault for not keeping an eye on the new build.

It was the newest build as well.

It was only 4.8bil lost, worked up from a starting point of 800mil - I rescued around 500mil by cancelling orders when I got back and had run out of isk so I'll get up there again.

Stupidly I've had logging off since things had seemed to settle after the patch. Derp.

Lesson learned. Time to start grinding the small orders again

Lets gift you one 90d license for trader to make you happier. Create an order using manual payment I will activate it for free.

I will add really strong protection against input errors on stage of the order modification. Bot will select and copy entered string before continue and will compare entered string with initial value.

Unexpected, unnecessary (it's my fault for being dumb and not watching it) and massively appreciated <3