diff --git a/Build-Binary.command b/Build-Binary.command
index 1da9a6a71..65e913da6 100755
--- a/Build-Binary.command
+++ b/Build-Binary.command
@@ -123,6 +123,9 @@ class create_binary:
             if file.name in delete_files:
                 print(f"  - Deleting {file.name}")
                 file.unlink()
+            elif (Path(file) / Path("Contents/Resources/createinstallmedia")).exists():
+                print(f"  - Deleting {file}")
+                subprocess.run(["rm", "-rf", file])
 
     def download_resources(self):
         patcher_support_pkg_version = constants.Constants().patcher_support_pkg_version
diff --git a/gui/gui_main.py b/gui/gui_main.py
index 1dbc373e6..d42ce245c 100644
--- a/gui/gui_main.py
+++ b/gui/gui_main.py
@@ -31,6 +31,7 @@ class wx_python_gui:
         self.finished_cim_process = False
         self.target_disk = ""
         self.pulse_forward = False
+        self.prepare_result = False
         self.non_metal_required = self.use_non_metal_alternative()
         self.hyperlink_colour = (25, 179, 231)
 
@@ -1832,9 +1833,8 @@ class wx_python_gui:
             20
         )
         self.progress_bar.Centre(wx.HORIZONTAL)
-        self.progress_bar.SetValue(0)
 
-        self.progress_label = wx.StaticText(self.frame, label="Bytes Written: 0")
+        self.progress_label = wx.StaticText(self.frame, label="Preparing files, beginning shortly...")
         self.progress_label.SetFont(wx.Font(12, wx.DEFAULT, wx.NORMAL, wx.NORMAL))
         self.progress_label.SetPosition(
             wx.Point(
@@ -1863,7 +1863,18 @@ class wx_python_gui:
         print("- Creating installer.sh script")
         print(f"- Disk: {disk}")
         print(f"- Installer: {installer_path}")
-        if installer.generate_installer_creation_script(self.constants.installer_sh_path, installer_path, disk):
+
+        self.prepare_script_thread = threading.Thread(target=self.prepare_script, args=(installer_path,disk))
+        self.prepare_script_thread.start()
+        self.progress_bar.Pulse()
+
+        while self.prepare_script_thread.is_alive():
+            self.pulse_alternative(self.progress_bar)
+            wx.GetApp().Yield()
+
+        if self.prepare_result is True:
+            self.progress_label.SetLabel("Bytes Written: 0")
+            self.progress_label.Centre(wx.HORIZONTAL)
             print("- Sucessfully generated creation script")
             print("- Starting creation script as admin")
             wx.GetApp().Yield()
@@ -1875,6 +1886,7 @@ class wx_python_gui:
             self.download_thread = threading.Thread(target=self.download_and_unzip_pkg)
             self.download_thread.start()
             default_output = float(utilities.monitor_disk_output(disk))
+            self.progress_bar.SetValue(0)
             while True:
                 time.sleep(0.1)
                 output = float(utilities.monitor_disk_output(disk))
@@ -1918,8 +1930,15 @@ class wx_python_gui:
                         self.build_install_menu()
         else:
             print("- Failed to create installer script")
+            self.progress_label.SetLabel("Failed to copy files to tmp directory")
+            self.progress_label.Centre(wx.HORIZONTAL)
+            popup_message = wx.MessageDialog(self.frame, "Failed to prepare the base files for installer creation.\n\nPlease ensure you have 20GB~ free on-disk before starting to ensure the installer has enough room to work.", "Error", wx.OK)
+            popup_message.ShowModal()
         self.return_to_main_menu.Enable()
 
+    def prepare_script(self, installer_path, disk):
+        self.prepare_result = installer.generate_installer_creation_script(self.constants.payload_path, installer_path, disk)
+
     def start_script(self):
         utilities.disable_sleep_while_running()
         args = [self.constants.oclp_helper_path, "/bin/sh", self.constants.installer_sh_path]
diff --git a/resources/installer.py b/resources/installer.py
index e13b3c7e4..0217087cc 100644
--- a/resources/installer.py
+++ b/resources/installer.py
@@ -3,6 +3,7 @@ from pathlib import Path
 import plistlib
 import subprocess
 import requests
+import tempfile
 from resources import utilities, tui_helpers
 
 def list_local_macOS_installers():
@@ -331,8 +332,10 @@ def list_disk_to_format():
         })
     return list_disks
 
+# Create global tmp directory
+tmp_dir = tempfile.TemporaryDirectory()
 
-def generate_installer_creation_script(script_location, installer_path, disk):
+def generate_installer_creation_script(tmp_location, installer_path, disk):
     # Creates installer.sh to be piped to OCLP-Helper and run as admin
     # Goals:
     # - Format provided disk as HFS+ GPT
@@ -341,6 +344,29 @@ def generate_installer_creation_script(script_location, installer_path, disk):
     # OCLP-Helper once to avoid nagging the user about permissions
 
     additional_args = ""
+    script_location = Path(tmp_location) / Path("Installer.sh")
+
+    # Due to a bug in createinstallmedia, running from '/Applications' may sometimes error:
+    #   'Failed to extract AssetData/boot/Firmware/Manifests/InstallerBoot/*'
+    # This affects native Macs as well even when manually invoking createinstallmedia
+
+    # To resolve, we'll copy into our temp directory and run from there
+
+    # Create a new tmp directory
+    # Our current one is a disk image, thus CoW will not work
+    global tmp_dir
+    ia_tmp = tmp_dir.name
+
+    print(f"Creating temporary directory at {ia_tmp}")
+    # Delete all files in tmp_dir
+    for file in Path(ia_tmp).glob("*"):
+        subprocess.run(["rm", "-rf", str(file)])
+
+    # Copy installer to tmp (use CoW to avoid extra disk writes)
+    subprocess.run(["cp", "-cR", installer_path, ia_tmp])
+
+    # Adjust installer_path to point to the copied installer
+    installer_path = Path(ia_tmp) / Path(Path(installer_path).name)
 
     createinstallmedia_path = str(Path(installer_path) / Path("Contents/Resources/createinstallmedia"))
     plist_path = str(Path(installer_path) / Path("Contents/Info.plist"))