Not Enough Disk Space Installing to Compressed Drive

• Microsoft Office 97 for Windows
• Microsoft Office for Windows 95, version 7.0
• Microsoft Office for Windows, versions 4.0, 4.2
• Microsoft Project for Windows, version 4.0
• Microsoft Works for Windows, version 3.0

SYMPTOMS

When you install a program to a compressed drive, you may receive a "disk full" error message. This behavior may occur after the Setup program indicates (at the beginning of the installation) that you have sufficient disk space to install all of the desired components.

CAUSE

When you install to a compressed drive, the amount of disk space reported as being available may be misleading depending on the types of files that are on the compressed drive and how effective the disk compression technology is when you compress different types of data. Because this number may be incorrect, you may need significantly more disk space than is reported as being required by setup.

MORE INFORMATION

You are most likely to run into this problem if the types of files that are being installed to the compressed drive are files that cannot be effectively compressed by the disk compression method being used.

For example, the clip art files that come with PowerPoint version 4.0 for Windows are in a special PictureStore format (*.pcs) that is so highly compressed that they cannot be compressed any more. If your compression technology is assuming an average compression ratio of 2:1, this means that for each 1 megabyte (MB) of *.pcs files that you choose to install, you would actually need to have 2 MB of compressed drive space available. PowerPoint includes over 5 MB of *.pcs files, so when you install to a 2:1 compressed drive, you will need 5 MB more available disk space than setup says is required.

STATUS

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.