diff --git a/src/make.tcl b/src/make.tcl
index 8402c0b1..a9c40c35 100644
--- a/src/make.tcl
+++ b/src/make.tcl
@@ -2898,17 +2898,18 @@ foreach vfstail $vfs_tails {
                             package require punk::zip
                             #tcl we are calling with doesn't have zipfs - can't mount
                             puts stderr "WARNING: tcl shell '[info nameofexecutable]' being used to build doesn't have zipfs - falling back to punk::zip::extract_preamble"
-                            set extractedzip $buildfolder/extracted_$runtime_fullname.zip
+                            set extractedzipfile $buildfolder/extracted_$runtime_fullname.zip
+                            set extractedzipfolder $buildfolder/extracted_$runtime_fullname
                             file delete $raw_runtime
-                            file delete $extractedzip
-                            file delete -force $buildfolder/extracted_$runtime_fullname
-                            punk::zip::extract_preamble $building_runtime $raw_runtime $extractedzip
+                            file delete $extractedzipfile
+                            file delete -force $extractedzipfolder
+                            punk::zip::extract_preamble $building_runtime $raw_runtime $extractedzipfile
                             package require zipfile::decode
-                            zipfile::decode::open $extractedzip
+                            zipfile::decode::open $extractedzipfile
                             set archiveinfo [zipfile::decode::archive]
-                            zipfile::decode::unzip $archiveinfo extracted_$runtime_fullname
+                            zipfile::decode::unzip $archiveinfo $extractedzipfolder
                             #todo - verify that init.tcl etc are present?
-                            merge_over $buildfolder/extracted_$runtime_fullname $targetvfs
+                            merge_over $extractedzipfolder $targetvfs
                         }
 
                         merge_over $sourcefolder/vfs/_vfscommon.vfs $targetvfs