Problem scenario
There is unaccounted for hard drive space missing. There is a discrepancy with the hard disk specifications of your machine and what you see during the installation of Linux (e.g., Ubuntu, RHEL, Stream Fedora, SUSE etc.). You are trying to designate an installation destination of the OS. Where is the missing space?
Possible Solutions
There are multiple potential root causes for this situation.
Possible Solution #1
Do a factory reset. WARNING: This will delete all of your data on the disk. Only do this if you do not need any files on your server. When you boot up press F11 repeatedly (for HP https://www.businessinsider.com/how-to-factory-reset-hp-laptop or Lenovo https://smallbusiness.chron.com/reformat-lenovo-laptop-54339.html). With Dell you log in https://www.gadgetsalvation.com/blog/2021/08/10/how-to-factory-reset-a-dell-laptop/. For some Lenovos you will use a physical button described in this video: https://support.lenovo.com/us/en/videos/vid100759-how-to-reset-your-laptop-to-factory-defaults-using-lenovo-onekey-recovery-okr
Possible Solution #2
This will delete all the data on your laptop.Sometimes a bootable .iso of a trial Windows OS can help you reformat and consolidate the disk space. Using Rufus (the installation tool) and a free version of Windows, you could reallocate disk space.
Possible Solution #3
See this posting: https://unix.stackexchange.com/questions/457721/usb-boot-install-linux-not-recognizing-disk-space
Possible Solution #4
See this Quora posting. It explains that there is no actual problem. As does this answer.