120G must be hard drive space and not memory since memory maxes out for most systems at 12G

right click on the computer icon on the desktop or in windows explorer and select properties the window will show installed memory (RAM)

Resolution for '20GB free issue: 'install error stating “only 3mb free” but have over 20GB free' available: Yes.

The 20GB free issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the 20GB free issue yourself by looking for a resolution described in the article. If it is a complex 20GB free issue or you are unable to solve the issue, you may contact us by clicking here or by using other 20GB free support options.

For more information about resolving issues related to 20GB free in Quickbooks/QBO or to get support for the issue 'install error stating “only 3mb free” but have over 20GB free', click the link below: