diff --git a/.idea/ballisticacore.iml b/.idea/ballisticacore.iml
index 174dfacf..045879af 100644
--- a/.idea/ballisticacore.iml
+++ b/.idea/ballisticacore.iml
@@ -56,6 +56,7 @@
       <excludePattern pattern="vssver2.scc" />
       <excludePattern pattern="manifest.json" />
       <excludePattern pattern=".spinoffdata" />
+      <excludePattern pattern=".asset_manifest_*.json" />
     </content>
     <orderEntry type="jdk" jdkName="Python 3.7" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/Makefile b/Makefile
index 1128d8de..ec041c20 100644
--- a/Makefile
+++ b/Makefile
@@ -138,7 +138,7 @@ prefab-release-build:
 
 # Specific platform prefab targets:
 
-prefab-mac-debug: prefab-mac-build
+prefab-mac-debug: prefab-mac-debug-build
 	@cd build/prefab/mac/debug && ./ballisticacore
 
 prefab-mac-debug-build: assets-cmake build/prefab/mac/debug/ballisticacore
@@ -178,7 +178,7 @@ build/prefab/linux/release/ballisticacore: .efrocachemap
 PREFAB_WINDOWS_PLATFORM = x64
 
 prefab-windows-debug: prefab-windows-debug-build
-	@echo Build succesful - now run:\
+	@echo Build successful - now run:\
  build/prefab/windows/debug/BallisticaCore.exe
 
 prefab-windows-debug-build: assets-windows \
@@ -189,7 +189,7 @@ build/prefab/windows/debug/BallisticaCore.exe: .efrocachemap
 	@tools/snippets efrocache_get $@
 
 prefab-windows-release: prefab-windows-release-build
-	@echo Build succesful - now run:\
+	@echo Build successful - now run:\
  build/prefab/windows/release/BallisticaCore.exe
 
 prefab-windows-release-build: assets-windows \
@@ -200,10 +200,11 @@ build/prefab/windows/release/BallisticaCore.exe: .efrocachemap
 	@tools/snippets efrocache_get $@
 
 # Tell make which of these targets don't represent files.
-.PHONY: prefab-mac prefab-mac-build prefab-mac-release \
- prefab-mac-release-build prefab-linux prefab-linux-build prefab-linux-release \
- prefab-linux-release-build prefab-windows-debug prefab-windows-debug-build \
- prefab-windows-release prefab-windows-release-build
+.PHONY: prefab-debug prefab-debug-build prefab-release prefab-release-build \
+ prefab-mac-debug prefab-mac-debug-build prefab-mac-release \
+ prefab-mac-release-build prefab-linux-debug prefab-linux-debug-build \
+ prefab-linux-release prefab-linux-release-build prefab-windows-debug \
+ prefab-windows-debug-build prefab-windows-release prefab-windows-release-build
 
 
 ################################################################################
diff --git a/tools/efrotools/efrocache.py b/tools/efrotools/efrocache.py
index 8aba17ca..f59320f2 100644
--- a/tools/efrotools/efrocache.py
+++ b/tools/efrotools/efrocache.py
@@ -229,7 +229,9 @@ def _write_cache_file(staging_dir: str, fname: str) -> Tuple[str, str]:
 
     # Fancy pipe stuff which will give us deterministic
     # tar.gz files (no embedded timestamps)
-    run(f'tar cf - {fname} | gzip -n > {path}')
+    # Note: The 'COPYFILE_DISABLE' prevents mac tar from adding
+    # file attributes/resource-forks to the archive as as ._filename.
+    run(f'COPYFILE_DISABLE=1 tar cf - {fname} | gzip -n > {path}')
     return fname, hashpath
 
 
@@ -255,8 +257,10 @@ def _write_cache_files(fnames1: List[str], fnames2: List[str],
     # Clients initing their cache dirs can grab this as a starting point
     # which should greatly reduce the individual file downloads they have
     # to do (at least when first building).
+    # Note: The 'COPYFILE_DISABLE' prevents mac tar from adding
+    # file attributes/resource-forks to the archive as as ._filename.
     print('Writing starter-cache...')
-    run('cd build && tar -Jcf startercache.tar.xz efrocache'
+    run('cd build && COPYFILE_DISABLE=1 tar -Jcf startercache.tar.xz efrocache'
         ' && mv startercache.tar.xz efrocache')
 
     # Now finish up with the second set.