diff --git a/BUILD.md b/BUILD.md
index f8494b6..5e64476 100644
--- a/BUILD.md
+++ b/BUILD.md
@@ -104,23 +104,13 @@ Create a .rpm:
 
 ## Qubes OS
 
-<details>
-  <summary><i>:memo: Expand this section if you want to use containers instead of disposable qubes.</i></summary>
-  </br>
-
-  Create a Debian or Fedora-based development standalone qube with at least
-  8GB of private storage space, and follow the relevant instructions above for
-  the respective template.
-
-  Remember to set the environment variable `DZ_USE_CONTAINERS=1`, before executing
-  Dangerzone.
-
-  Over time, you may need to increase disk space or prune outdated container
-  images if you run into build issues on this VM.
-</details>
 
 > :warning: Native Qubes support is in alpha stage, so the instructions below
 > require switching between qubes, and are subject to change.
+>
+> If you want to build Dangerzone on Qubes and use containers instead of disposable
+> qubes, please follow the intructions of Fedora / Debian instead.
+
 
 ### Initial Setup
 
@@ -248,10 +238,10 @@ can run the following commands in the `dz` app qube:
 poetry shell
 
 # run the CLI
-./dev_scripts/dangerzone-cli --help
+QUBES_CONVERSION=1 ./dev_scripts/dangerzone-cli --help
 
 # run the GUI
-./dev_scripts/dangerzone
+QUBES_CONVERSION=1 ./dev_scripts/dangerzone
 ```
 
 Create a .rpm:
diff --git a/dangerzone/cli.py b/dangerzone/cli.py
index 1d31c05..2361399 100644
--- a/dangerzone/cli.py
+++ b/dangerzone/cli.py
@@ -6,11 +6,10 @@ import click
 from colorama import Back, Fore, Style
 
 from . import args, errors
-from .conversion.common import running_on_qubes
 from .document import ARCHIVE_SUBDIR, SAFE_EXTENSION
 from .isolation_provider.container import Container
 from .isolation_provider.dummy import Dummy
-from .isolation_provider.qubes import Qubes
+from .isolation_provider.qubes import Qubes, is_qubes_native_conversion
 from .logic import DangerzoneCore
 from .util import get_version
 
@@ -65,7 +64,7 @@ def cli_main(
 
     if getattr(sys, "dangerzone_dev", False) and dummy_conversion:
         dangerzone = DangerzoneCore(Dummy())
-    elif running_on_qubes():
+    elif is_qubes_native_conversion():
         dangerzone = DangerzoneCore(Qubes())
     else:
         dangerzone = DangerzoneCore(Container(enable_timeouts=enable_timeouts))
diff --git a/dangerzone/conversion/common.py b/dangerzone/conversion/common.py
index 5f6de42..93cd1b2 100644
--- a/dangerzone/conversion/common.py
+++ b/dangerzone/conversion/common.py
@@ -19,10 +19,7 @@ TIMEOUT_MIN: float = 60  # (seconds)
 
 def running_on_qubes() -> bool:
     # https://www.qubes-os.org/faq/#what-is-the-canonical-way-to-detect-qubes-vm
-    if os.environ.get("DZ_USE_CONTAINERS", "0") == "0":
-        return os.path.exists("/usr/share/qubes/marker-vm")
-    else:
-        return False
+    return os.path.exists("/usr/share/qubes/marker-vm")
 
 
 async def read_stream(
diff --git a/dangerzone/gui/__init__.py b/dangerzone/gui/__init__.py
index 1e5495b..08fa44e 100644
--- a/dangerzone/gui/__init__.py
+++ b/dangerzone/gui/__init__.py
@@ -21,11 +21,10 @@ else:
         from PySide2 import QtCore, QtGui, QtWidgets
 
 from .. import args, errors
-from ..conversion.common import running_on_qubes
 from ..document import Document
 from ..isolation_provider.container import Container
 from ..isolation_provider.dummy import Dummy
-from ..isolation_provider.qubes import Qubes
+from ..isolation_provider.qubes import Qubes, is_qubes_native_conversion
 from ..util import get_resource_path, get_version
 from .logic import DangerzoneGui
 from .main_window import MainWindow
@@ -105,7 +104,7 @@ def gui_main(
     if getattr(sys, "dangerzone_dev", False) and dummy_conversion:
         dummy = Dummy()
         dangerzone = DangerzoneGui(app, isolation_provider=dummy)
-    elif running_on_qubes():
+    elif is_qubes_native_conversion():
         qubes = Qubes()
         dangerzone = DangerzoneGui(app, isolation_provider=qubes)
     else:
diff --git a/dangerzone/isolation_provider/qubes.py b/dangerzone/isolation_provider/qubes.py
index 9a9eb9d..7ddb9be 100644
--- a/dangerzone/isolation_provider/qubes.py
+++ b/dangerzone/isolation_provider/qubes.py
@@ -19,8 +19,9 @@ from .base import IsolationProvider
 
 log = logging.getLogger(__name__)
 
+from ..conversion.common import running_on_qubes
 from ..conversion.pixels_to_pdf import PixelsToPDF
-from ..util import get_subprocess_startupinfo, get_tmp_dir
+from ..util import get_resource_path, get_subprocess_startupinfo, get_tmp_dir
 
 CONVERTED_FILE_PATH = (
     # FIXME won't work for parallel conversions (see #454)
@@ -173,3 +174,20 @@ class Qubes(IsolationProvider):
         bufsize_bytes = len(temp_file.getvalue()).to_bytes(4)
         wpipe.write(bufsize_bytes)
         wpipe.write(temp_file.getvalue())
+
+
+def is_qubes_native_conversion() -> bool:
+    """Returns True if the conversion should be run using Qubes OS's diposable
+    VMs and False if not."""
+    if running_on_qubes():
+        if getattr(sys, "dangerzone_dev", False):
+            return os.environ.get("QUBES_CONVERSION", "0") == "1"
+
+        # XXX If Dangerzone is installed check if container image was shipped
+        # This disambiguates if it is running a Qubes targetted build or not
+        # (Qubes-specific builds don't ship the container image)
+
+        compressed_container_path = get_resource_path("container.tar.gz")
+        return not os.path.exists(compressed_container_path)
+    else:
+        return False