You should have Glidos.pif and GlidosF.pif files in your Glidos directory. If not, try reinstalling Glidos.

Kaminari, I thank you for your quick response.

The files Glidos.pif and GlidosF.pif were missing from the Glidos directory. What could cause these two files to disappear?

Not knowing what would happen when I reinstalled Glidos, I first copied the Glidos and Tombraid directories to folders on another partition on my hard drive. After reinstalling Glidos I compared the directories with Windiff.

The Tombraid directory didn't change, but Windiff reported that Glidos.ini was changed (reset to default values) and Glidos.pif and GlidosF.pif were only in the directory on the C drive. The two files in the Glidos directory did not show a .pif extension in the directory listing. So files of the type "Shortcut to MS-DOS Program" without an extension are .pif files. I didn't know that. I learn something new every day.

When I looked at the Glidos.ini file, I saw that the Tomb Raider section has a line "VESASupport: Yes" and that line is not present in the Unfinished Business section. The Tomb.exe and TombUB.exe programs would seem to do essentially the same thing in their respective games, so why is VESA Support necessary or desirable in the one and not in the other?

I also looked at the OpenGLid.log file. Down under OpenGL Extensions there is a line "Note: OpenGL GL_SGIS_generate_mipmap extension is supported but disabled by user" and another line "Note: OpenGL GL_EXT_vertex_array extension is supported but disabled by user."

At first I thought that this might the result of something that I did wrong, but in the OpenGLid.ini file I see lines "EnableMipMaps=0" and "EnableVertexArrayEXT=0", so I thought that that's probably where those items are disabled. So what do these two things do, and is it a good thing or a bad thing that they are disabled?

I was running Glidos v1.24. I saw on the forum a mention of v1.25, so I just downloaded and installed it. Comparing v1.25 to v1.24 I find that VESA Support has been added to Unfinished Business and EnableMipMaps has been set to 1. So 1 1/2 of my questions have been answered.

I discovered that the reason that the Glidos.pif and GlidosF.pif files were missing was that Norton's WinDoctor considered them to be invalid shortcuts and removed them. Their Cmd line entrys pointed to file Glidos.bat, but that file is not in the Glidos directory, but rather in the C:/TOMBRAID directory.

I edited the Cmd lines for the two files to point to C:\TOMBRAID\Glidos.bat and WinDoctor was happy.

That's useful to know... although the better solution might be to get rid of Norton WinDoctor: there are already too many parts of Windows that second guess you rather than doing what they are told.

Ah yes, there is a problem with what you've done. You now have a set up where Glidos will always start TR1, whichever game you select from the menu.

I see your point. However, Tomb Raider and Unfinished Business are the only games that I play using Glidos, and they are both in the same directory, and they both work, so it works for me and WinDoctor is happy.

WinDoctor may not be perfect, but it has done more good things for me than bad.

OK. The final solution. I restored the two .pif files to their standard form, then put a copy of the Glidos.bat file in the Glidos directory.

So the .pif files will work with any of the games supported by Glidos, and Norton's WinDoctor reports no invalid shortcuts .

Ah yes. Nice solution. Even an empty Glidos.bat would do. I'll change the installer to include one.