diff --git a/.Rbuildignore b/.Rbuildignore
index 689f0329a..a88f92561 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -43,3 +43,5 @@ _files$
 ^compile_commands\.json$
 ^\.cache$
 ^tests/testthat/helper-rethrow\.R$
+^cleanup$
+^cleanup\.win$
diff --git a/.github/workflows/install/action.yml b/.github/workflows/install/action.yml
index 702aedabd..9d367ea3a 100644
--- a/.github/workflows/install/action.yml
+++ b/.github/workflows/install/action.yml
@@ -56,6 +56,8 @@ runs:
         echo "_R_CHECK_UNDOC_USE_ALL_NAMES_=true" | tee -a $GITHUB_ENV
         echo "_R_CHECK_URLS_SHOW_301_STATUS_=true" | tee -a $GITHUB_ENV
         echo "_R_CXX_USE_NO_REMAP_=true" | tee -a $GITHUB_ENV
+        echo "_R_CHECK_CRAN_INCOMING_=true" | tee -a $GITHUB_ENV
+        echo "_R_CHECK_CRAN_INCOMING_SKIP_LARGE_VERSION_=true" | tee -a $GITHUB_ENV
       shell: bash
 
     - name: Set environment variables (non-Windows only)
diff --git a/.gitignore b/.gitignore
index 38f9248b9..69de8bcd3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -103,6 +103,7 @@ $RECYCLE.BIN/
 *.tgz
 src/**/*.o
 src/*.so
+src/*.dll
 /scripts/__pycache__
 /duckdb
 /src/Makevars.duckdb
diff --git a/cleanup b/cleanup
new file mode 100755
index 000000000..567ba913f
--- /dev/null
+++ b/cleanup
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+set -ex
+
+git clean -fdx src
+cd src
+tar cvJf duckdb.tar.xz duckdb
+rm -rf duckdb
diff --git a/cleanup.win b/cleanup.win
new file mode 100644
index 000000000..567ba913f
--- /dev/null
+++ b/cleanup.win
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+set -ex
+
+git clean -fdx src
+cd src
+tar cvJf duckdb.tar.xz duckdb
+rm -rf duckdb
diff --git a/configure b/configure
index 2d00e6308..3b9189ac9 100755
--- a/configure
+++ b/configure
@@ -27,3 +27,10 @@ if [ -f "${DUCKDB_R_PREBUILT_ARCHIVE}" ] && tar -xm -f ${DUCKDB_R_PREBUILT_ARCHI
 else
   cp include/to-tar.mk Makevars.duckdb
 fi
+
+# The duckdb sources are xz-compressed in the tarball to keep it under 5000000 bytes.
+# This happens in the cleanup script.
+
+if [ -f duckdb.tar.xz ]; then
+  tar xJf duckdb.tar.xz
+fi
diff --git a/configure.win b/configure.win
index 5e95002ac..9e6a17549 100755
--- a/configure.win
+++ b/configure.win
@@ -33,3 +33,11 @@ if [ -f "${DUCKDB_R_PREBUILT_ARCHIVE}" ] && tar -xm --force-local -f ${DUCKDB_R_
 else
   cp include/to-tar-win.mk Makevars.duckdb
 fi
+
+# The duckdb sources are xz-compressed in the tarball to keep it under 5000000 bytes.
+# This happens in the cleanup script.
+
+if [ -f duckdb.tar.xz ]; then
+  tar xJf duckdb.tar.xz
+  find duckdb -type f | xargs unix2dos
+fi