Astah project files (.asta) are upward compatible. If project files are edited by new version, they cannot be opened in older version of Astah.
For information about model versions, click here.
If you cannot open project files using appropriate version of Astah, please change the stack size.

Version 6.2.x or later

1. Open [Tool]-[System Properties]-[File] and specify the appropriate stack size
   
2. Click [Apply]-[OK] and restart Astah

Version 6.1.1 or before

1. Open Astah batch file (astah-pro.bat or astah.bat) with Text Editor. You can find in Astah Installation folder
2. Find the following line
   
   • "set STACK_SIZE=2m"
3. Change "2m" to 3m" or appropriate size
4. Save the batch file and start Astah