沒有玩過，不過手癢 search 了一下，或許可以參考看看這篇文章，引用一下 70 樓的回應。

follow the instructions below

1. start ur gns3
2. a small dialog boz appears
   3.type in any name & check marks both the options below it.
   4.after creating a topology start the routers & enter some configuration in them.then in privilge exec mode type WR to save ur config.
3. once u save it , without stopping the routers go to main gns3 window.
   6.click on file > save
   7.then stop ur routers & play them again..that is it.
   8.next time when u want to open the same topology just click on file>open & click on the file u want to load.

感覺重點在於，一定要開一個全新的project，並且每次將ROUTER設定存檔後，都要退出來主視窗存一次檔。

也有人提到把 xx.cfg 放到 working directory 去 (64 樓)，祝好運。