If I reinstall OSX will I lose information I did not back up

If it was caused by a software problem, see above.

If it was caused by disk structure damage, you should try repairing it instead of reinstalling the OS.

If it was caused by a hardware problem, you won't be able to reinstall the OS; in many cases, the drive won't appear in the Disk Utility.

If you can access the drive, use the Image or Restore function in the Disk Utility, and copy the files to an external one.

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Before you reinstall it, why not do a Time Machine backup? Better to be safe than sorry....

Or are you indicating that you need to reinstall because you already are having an issue, and can only do the reinstall at this point? If so, then fingers crossed that all goes well!

Best,

GB

Only if a problem occurs.

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