32 process limit on NT

I use p4.el (Perforce VC mode), which executes call-process every time it opens a file to check whether the file is under source control. After a while, I get: Signaling: (file-error "Spawning child process" "Resource temporarily unavailable") call-process-internal("\\Perforce\\p4.exe" nil "*P4 Output*" nil "files" "c:\\src\\session\\src\\ssexplain.cpp") apply(call-process-internal "\\Perforce\\p4.exe" nil "*P4 Output*" nil ("files" "c:\\src\\session\\src\\ssexplain.cpp")) call-process("\\Perforce\\p4.exe" nil "*P4 Output*" nil "files" "c:\\src\\session\\src\\ssexplain.cpp") p4-is-vc() p4-check-mode() p4-find-file-hook() run-hooks(p4-find-file-hook) after-find-file(nil t) find-file-noselect("c:\\src\\session\\src\\ssexplain.cpp") find-file("c:\\src\\session\\src\\ssexplain.cpp" nil) call-interactively(find-file) I presume this is the 32 process maximum discusses in "ediff eats handles" thread. Are there any workarounds? Interestingly, the limit does not seem to apply to processes called from compile. Thanks, Gleb PS This is in 21.0 "Zhong Wei" Fabrice's binaries.