"Too many files open" error

"Too many files open" error

Microsoft in its infinite wisdom decided that by default your computer should allow only a limited number of files to be opened at any one time on your computer. Perhaps it's a leftover from the days when computers only had a megabyte of memory. Or perhaps they hoped that if you got the "Too many files open" error you'd go out and buy a newer, more powerful system - from them again of course. Whatever the reason, if you run a database program such as dBase, FoxPro, Visual FoxPro, etc., and open a large number of files at one time, you will in time encounter this error. Once you have triggered this error, your session is corrupted and you have to reboot your computer.

The maximum number of files is set in the computer's configuration files and you can raise the limit easily. But each version of Windows has different methods and locations for storing this setting.

Windows Millennium by default has 30 files set internally. With a theoretical maximum of 255, subtract 30 and you are left with 225 files that you can add yourself. While Windows Millennium limits the user to 225 additional files, the other Windows versions probably allow the number up to 255. In any case, most users will never need a setting higher than 80 to 100. In my examples below I will use 100 since it is a reasonably high number but not absurdly high.

Windows 95
Windows 98
Windows 98se

Location: C:\CONFIG.SYS
Line: FILES=100

Windows NT
Windows 2000

Location: C:\WinNT\System32\CONFIG.NT
Line: FILES=100

Windows XP

Location: C:\Windows\System32\CONFIG.NT
Line: FILES=100

Windows Millennium

Go to Start/Run and run MSCONFIG
Select System.ini tab
Select [386Enh]
Click on the + on the left of that line to display its contents
If an entry for PerVMFiles does not exist, then click the New button
and type: PerVMFiles=100
Confirm by clicking on OK or Apply.

Special note for Windows Millennium users: Microsoft's support page linked below says that "16-Bit Programs Cannot Open More Than 120 Files Simultaneously in Windows Me". They have a fix you can download to update Dosmgr.vxd, but most users never have a need to open more than 120 files at a time anyway. I never have in 20 years' of programming.
http://support.microsoft.com/default.aspx?scid=kb;en-us;274594