# Missing Conditional Compilation Symbols

**URL:** <https://clarionhub.com/t/missing-conditional-compilation-symbols/4045>\
**Category:** questions\
**Tags:** fm3, ide, c11\
**Created:** [April 15, 2021, 4:18am UTC](https://clarionhub.com/t/missing-conditional-compilation-symbols/4045 "2021-04-15T04:18:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![DonnEdwards](https://clarionhub.com/user_avatar/clarionhub.com/donnedwards/32/1047_2.png) [@DonnEdwards](https://clarionhub.com/u/DonnEdwards)\
**Post date:** [April 15, 2021, 4:18am UTC](https://clarionhub.com/t/missing-conditional-compilation-symbols/4045/1 "2021-04-15T04:18:55Z")

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My NetTalk server app uses quite a few conditional compilation symbols, most of which are (mercifully) handled for me.

 ![Conditional](https://clarionhub-uploads.s3.dualstack.eu-north-1.amazonaws.com/original/2X/b/b2039939c0b2c34cd757f65d65d686c86c31cd03.png)

But from time to time, for no reason I can determine, all these symbols disappear. The entire set, including FM2=\>1 which FileManager3 needs.

I was editing an embed, which I saved, and then I clicked "Start without Debugger (Builds solution)" and poof! **All gone** and the build failed because FM2=\>1 was missing.

Am I doing something wrong? Is this a known bug in C11?

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<div class="post-metadata">

**Author:** ![DonnEdwards](https://clarionhub.com/user_avatar/clarionhub.com/donnedwards/32/1047_2.png) [@DonnEdwards](https://clarionhub.com/u/DonnEdwards)\
**Post date:** [April 18, 2021, 12:35pm UTC](https://clarionhub.com/t/missing-conditional-compilation-symbols/4045/2 "2021-04-18T12:35:04Z")

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I think _Backup and Sync from Google_ may have been interfering with the build process by locking files in use. I have disabled it using **pskill.exe** in a scheduled task and the problem hasn’t repeated itself.