Hello,

I wanted to format one partition on my computer which had to be cleaned but accidentally chose another partition (partition D) where all the important data is stored. The formatting was at slow speed (the check mark was removed from "Quick Format" option before the formatting started). After 9 percent of the partition had been formatted, I realized that I had chosen a wrong partition with all the important data on it. I instantly terminated the formatting process by switching off the computer to make sure that the process stops immediately. Now Windows system says that the partition is not accessible.

Does anyone know how to restore the data in the partition and regain access to it?

The data on the 9% you had formated is gone
The rest you can try run a DR software like r-studio Etc. on that partition

Try install getdataback for NTFS and Recover through sudden partition loss option.

Thank you for the information. Data Rescue PC3 is listed as the best software at https://www.google.ru/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwi2qdvo6IfOAhXIHpoKHQCfDVcQFghHMAM&url=http%3A%2F%2Fdata-recovery-software-review.toptenreviews.com%2F&usg=AFQjCNFZSyjsDvIwsDMXO7wIhhm-z6KSzQ&sig2=XnTgQ_0-mHOF8ufaEO4aTA

The installation file is only about 7 mb in size. Does anyone know whether Data Rescue PC3 is a good software for restoring data from a damaged or formatted drive partition?

Ahh yes. Because that's a fake review. Try GetDataBack or R-Studio.

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On a clear disk you can seek forever.