1.The Janome 300E works with flashcards. Have you got the card and the adapter? I've never seen a magic box so I don't know what it does but you don't need one for the Janome.
2. Put your card in the Janome and turn it on. This will format the flashcard.
3. Janome doesn't use .pes format, it uses .jef!
4. If you need to convert designs from any other format to .jef go to the website http://www.myembroideryhaven.com and download software from there to convert.
5. Simply put your flashcard into the appropriate slot on your computer (I use a slot in my printer) and save to the EMB file on the card. Insert into the Janome and off you go.

Thank you so much for your help.I have the adapter and cards for the 300E.Also have the Janome 9000 MC that the Magic Box was bought for.Found the instructions for it on its CD, after my posting.I think it is the same as the Amazing Box.So now we can do .sew and .jef both,I hope.Have had the 9000 since 1999,and just got the 300E.But I'm having a ball,but for some reason DH hid his underwear that I had put "I'm Boss" on.LOL Thanks again,Netta

I have a Janome 300E and a magic box. I just put the card in the right slot and find the design that I want and save it to the card. You can save several designs on the card. I have problems with my Janome 300E. The thread balls up and I have to undo and pull thread and start all over. They changed the bobbin case last time and I am kind of scared to try. It has messed up a few things. I hope this works

I'm sorry you've had problems. I find the Janome likes things to be well stabilised. I never hoop the fabric, but hoop a tear away, then depending on the item, i.e. a t shirt, I spray baste a mesh stabiliser to the back of the t shirt, spray baste that to the tear away, then float a washaway on top. This thick sandwich gives perfect results every time.
Perhaps your tension isn't tight enough too. Test out on your oldest t shirt to see what happens!

I just purchased a 300e and was told to get an iogear 56-1 reader, writer, also I got a 16mg sandisk card. I thought I was going to transfer all of my designs on the sandisk card, only to find out it does not hold much.....around 25 designs. Could somebody tell me which card I can get that the 300e will hold the most? Also do I have to get a sandisk card or can I go to office depot? Reading some of the posts I find that I am suppose to format the card.......this all new to me. So I am going to need some help. Thanks

bella, you have prob already figured out that you don't need a card with larger memory. The machine cannot read and hold a large number of designs at any one time...so you should just 'erase or write over' as you want to add new designs. Remember, your originals are stored on your computer. Your software is a better choice than having to use the Magic Box, which only writes 6 designs at a time.