CHKDSK: Errors Detected in the Uppercase File (Fixed)

You will learn the cause and solution to chkdsk errors detected in the uppercase file and how to prevent data loss due to disk failure or chkdsk deleted files.


by Ivy Updated on October 17, 2022

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Cause and solution to chkdsk errors detected in the uppercase file

CHKDSK is a command line tool to check file system integrity and bad sectors of the hard drive and can recover file system and logical & physical errors. However, sometimes, you will be told the chkdsk errors detected in the uppercase file when you run chkdsk.exe tool on a hard disk. 

Usually, it occurs if you upgrade Microsoft Windows NT 3.5.1 to Windows NT 4.0 and your hard drive is formatted with the NTFS file system. And you can resolve this issue by using the Chkdsk.exe tool with the f switch. To do that, type chkdsk /f in the command prompt window and hit Enter to run it. And you may be asked to type Y and restart your computer to run this tool at the system startup. Please do as prompted.

Chkdsk F

Tip: The meaning of  “uppercase file” is an upper file named $UpCase in the NTFS formatted disk, and it is used to compare and sort file names. It is a list of all Unicode characters in uppercase, 128KB in size, and containins a Unicode uppercase conversion table.

How to prevent data loss due to file system error

Although the chkdsk can help you fix some of file system error or logical & physical error, but it cannot fix all of error. And it is possible to delete some files on your hard drive. To avoid data loss due to file system error of hard drive or chkdsk deleted files, you can choose to backup system including all the system files and personal data or directly backup disk.

To backup system, you need a free backup software - AOMEI Backupper Standard to help you. It allows you to schedule backup system with daily, weekly, monthly frequencies and the incremental backup is usually used with it to backup only changed files. And it still use normal compression, intelligent sector backup, automatic splitting to further reduce the size of backup image.

Please download this software and install it on your new computer. For server users, try AOMEI Backupper Server.

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Step 1. Run AOMEI Backupper, click “Backup” and choose “System Backup" subsequently.

System Backup

Step 2. Follow the prompts given by this software to choose the destination path to save backup file. The system and boot partitions are selected by default.  

Select Destination

Step 3. Confirm this operation and click “Start Backup” to create a system image on your computer.

It seems to be good since you don't need to backup system manually. And it is able to minimize the size of backup image using incremental backup, normal compression, intelligent sector backup, and automatic splitting. But in the long run, the disk space will be fulfilled due to accumulated backups. In this case, you can choose to delete old backups manually or automatically. 

If you do this manually, based on the nature of incremental backups, it is possible that all backups between two full backups will become invalid. Thus you need to enable Backup Scheme and delete backup file automatically. You have 3 options, By quantity,  By time, By daily/weekly/monthly. You need to upgrade now (5% off for one computer) before using it. 

Enable Automatic Backup Cleanup

At the same time, you can choose to use differential backup as backup method for the scheduled task, which completely compensates for this problem with incremental backups. For differences between them, please refer to: Incremental or Differential Backup.

Besides, you still can enable email notification to confirm if the backup task is completed successfully or not. Comment, split, compress the backup image, or select a backup mode, etc. 

AOMEI Email SMS Notification Settings


With backup image in hand, you can easily restore system image to new hard drive or SSD to avoid chkdsk error or other computer failures.

In case your computer will fail to boot, it's suggested to create bootable USB or recovery environment in Windows 7, 8, 10, 11. Both of them can help you boot computer from and perform system restore. The later one is able to add boot menu on the current computer, without requiring any storagde device.

Create Bootable Media


You can easily resolve the chkdsk errors detected in the uppercase file by using Chkdsk.exe with the F switch. To avoid data loss due to disk failure or chkdsk deleted files, you can choose to backup system on your computer, preferable a scheduled task.

Ivy · Editor
Ivy is an editor of AOMEI Technology, she covers backup & restore,hard disk & partitions management and cloud files transfer and so on for AOMEI. She is an outgoing girl and enjoys helping people find solutions to their problems. She loves traveling, eating, reading and so on. She usually hangs out with friends at her leisure time.