Windows Server 2019 Low Disk Space Alert on C Drive

This article explains why the C drive runs out of space and how to fix the low disk space alert in Windows Server 2019 quickly and safely.

1. Why Low Disk Space Alert in Windows Server 2019

Low disk space is a common issue in Windows Server 2019. The system C drive will easily become full over time, even if you created it with 50GB+ of space. This happens because Windows constantly generates junk files, such as temporary files, caches, and system logs. Additionally, Windows Updates, system backups, and shadow copies consume a large amount of free space rapidly.

When the C drive is almost full, the server performance will decrease. It may run slowly, get stuck, or even reboot unexpectedly. To alert administrators, Windows will pop up a "Low Disk Space" warning, and the C drive will show as red in File Explorer. When you see this alert, you should fix this issue as fast as possible to prevent a system crash.

2. How to Fix Low Disk Space on Windows Server 2019

Step 1: Clean Up Disk to Reclaim Free Space

To free up disk space, Windows Server 2019 provides a native Disk Cleanup tool. It is safe, fast, and able to delete most types of junk files without damaging the operating system.

Follow the steps to free up space with Windows Server 2019 Disk Cleanup:

1. Press the Windows key + R simultaneously on your keyboard to launch the Run box.
2. Type cleanmgr and press Enter.
3. Select the C: drive from the drop-down menu and click OK to scan.
4. Select the checkboxes next to the file categories you wish to clear, click OK, and confirm the permanent deletion.

If you want to automate this task, follow the guide to clean up disk with cleanmgr command.

Step 2: Add More Free Space to C Drive

With safe partition software, you can shrink other data partitions on the same disk to get Unallocated space, and then add this space to the C drive. In this way, the Operating System, programs, and everything else keep the same as before.

There are many partition tools on the market, but you should back up the server and run safe software to avoid the risk of data loss. Better than other tools, NIUBI Partition Editor offers premium data protection and faster file processing:

• Virtual Mode – All operations are listed as pending for preview. Real disk partitions won't be modified until you click "Apply" to confirm.
• Cancel-at-will – You can cancel ongoing operations safely at any progress without losing data or damaging partitions.
• 1-Second Rollback – If any known error is detected while modifying partitions, it automatically reverts the server to its original status instantly.
• Hot Clone – Clone the system disk or data partition without interrupting the server. You can boot from the cloned disk immediately if the primary disk fails.
• Advanced file-moving algorithm – 30% to 300% faster when shrinking, moving, or cloning partitions.

Download NIUBI Partition Editor and follow the instructions in the video tutorial to allocate more capacity to the system drive:

Add as much free space as possible to the C drive, and you won't see the low disk space warning again.

3. Additional Maintenance Options

1. Change the default download and output paths of your programs to a data partition.
2. Change the installation path to drive D or another volume when installing new applications.
3. Run Windows Disk Cleanup once a month to delete newly generated junk files.