# Convert back to cs3 form cs4

**URL:** <https://forum.kirupa.com/t/convert-back-to-cs3-form-cs4/280905>\
**Category:** flash\
**Created:** [February 2, 2009, 10:20pm UTC](https://forum.kirupa.com/t/convert-back-to-cs3-form-cs4/280905 "2009-02-02T22:20:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![BIGCURT](https://avatars.discourse-cdn.com/v4/letter/b/6f9a4e/32.png) [@BIGCURT](https://forum.kirupa.com/u/BIGCURT)\
**Post date:** [February 2, 2009, 10:20pm UTC](https://forum.kirupa.com/t/convert-back-to-cs3-form-cs4/280905/1 "2009-02-02T22:20:56Z")

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I have Flash CS4 but my school has CS3, i did a project in CS4 brought it to the school and the file will not open, what sould i do about this? :q: How do i change the file format? The error message was unable to open file format.