diff --git a/cloudvolume/__init__.py b/cloudvolume/__init__.py
index fdacfed2..6462eefb 100644
--- a/cloudvolume/__init__.py
+++ b/cloudvolume/__init__.py
@@ -65,7 +65,7 @@
 from . import exceptions
 from . import secrets
 
-__version__ = '12.1.1'
+__version__ = '12.2.0'
 
 # Register plugins
 from .datasource.precomputed import register as register_precomputed
diff --git a/cloudvolume/datasource/precomputed/image/tx.py b/cloudvolume/datasource/precomputed/image/tx.py
index 03394b94..f67f01ae 100644
--- a/cloudvolume/datasource/precomputed/image/tx.py
+++ b/cloudvolume/datasource/precomputed/image/tx.py
@@ -205,17 +205,19 @@ def upload_aligned(
     secrets=secrets
   )
 
-  parallel_execution(
-    cup, chunk_ranges, parallel, 
-    progress, desc="Upload", 
-    cleanup_shm=location
-  )
-
-  # If manual mode is enabled, it's the 
-  # responsibilty of the user to clean up
-  if not use_shared_memory:
-    array_like.close()
-    shm.unlink(location)
+  try:
+    parallel_execution(
+      cup, chunk_ranges, parallel, 
+      progress, desc="Upload", 
+      cleanup_shm=location
+    )
+  finally:
+    # If manual mode is enabled, it's the 
+    # responsibilty of the user to clean up
+    if not use_shared_memory:
+      del renderbuffer
+      array_like.close()
+      shm.unlink(location)
 
 def child_upload_process(
     meta, cache, 
@@ -267,6 +269,7 @@ def updatefn():
       secrets=secrets,
     )
   finally:
+    del renderbuffer
     array_like.close()
 
 def threaded_upload_chunks(
diff --git a/cloudvolume/frontends/precomputed.py b/cloudvolume/frontends/precomputed.py
index d0d715df..b3637596 100644
--- a/cloudvolume/frontends/precomputed.py
+++ b/cloudvolume/frontends/precomputed.py
@@ -1129,7 +1129,8 @@ def upload_from_shared_memory(self, location, bbox, order='F', cutout_bbox=None)
       order=order,
       use_shared_memory=True,
     )
-    mmap_handle.close()
+    del shared_image
+    # mmap_handle.close()
 
   def upload_from_file(self, location, bbox, order='F', cutout_bbox=None):
     """
@@ -1190,6 +1191,7 @@ def upload_from_file(self, location, bbox, order='F', cutout_bbox=None):
       order=order,
       use_file=True,
     )
+    del shared_image
     mmap_handle.close()
 
   def viewer(self, port=1337):
diff --git a/cloudvolume/sharedmemory.py b/cloudvolume/sharedmemory.py
index 79aaee56..75e6448e 100644
--- a/cloudvolume/sharedmemory.py
+++ b/cloudvolume/sharedmemory.py
@@ -127,8 +127,7 @@ def allocate_shm_file(filename, nbytes, dbytes, readonly):
 
 def ndarray_shm(shape, dtype, location, readonly=False, order='F', **kwargs):
   """Create a shared memory numpy array. Requires /dev/shm to exist."""
-  import posix_ipc
-  from posix_ipc import O_CREAT
+  from multiprocessing import shared_memory
   import psutil
 
   nbytes = Vec(*shape).rectVolume() * np.dtype(dtype).itemsize
@@ -170,21 +169,19 @@ def ndarray_shm(shape, dtype, location, readonly=False, order='F', **kwargs):
   # a threading condition where the condition of the shared memory
   # was adjusted between the check above and now. Better to make sure
   # that we don't accidently change anything if readonly is set.
-  flags = 0 if readonly else O_CREAT 
   size = 0 if readonly else int(nbytes) 
 
   try:
-    shared = posix_ipc.SharedMemory(location, flags=flags, size=size)
-    array_like = mmap.mmap(shared.fd, shared.size)
-    os.close(shared.fd)
-    renderbuffer = np.ndarray(buffer=array_like, dtype=dtype, shape=shape, order=order, **kwargs)
+    shm = shared_memory.SharedMemory(name=location, create=(not readonly), size=size)
+    renderbuffer = np.frombuffer(buffer=shm.buf, dtype=dtype)
+    renderbuffer = renderbuffer.reshape(shape, order=order)
   except OSError as err:
     if err.errno == errno.ENOMEM: # Out of Memory
-      posix_ipc.unlink_shared_memory(location)      
+      unlink_shm(location)
     raise
 
   renderbuffer.setflags(write=(not readonly))
-  return array_like, renderbuffer
+  return shm, renderbuffer
 
 def unlink(location):
   if EMULATE_SHM:
@@ -192,10 +189,11 @@ def unlink(location):
   return unlink_shm(location)
 
 def unlink_shm(location):
-  import posix_ipc
+  from multiprocessing import shared_memory
   try:
-    posix_ipc.unlink_shared_memory(location)
-  except posix_ipc.ExistentialError:
+    shm = shared_memory.SharedMemory(name=location, create=False)
+    shm.unlink()
+  except FileNotFoundError:
     return False
   return True
 
diff --git a/setup.py b/setup.py
index 4f65e7fb..89aabe16 100644
--- a/setup.py
+++ b/setup.py
@@ -35,7 +35,7 @@ def requirements():
 
 setuptools.setup(
   name="cloud_volume",
-  version="12.1.1",
+  version="12.2.0",
   setup_requires=[
     'numpy<1.17; python_version<"3.5"',
     'numpy; python_version>="3.5"',
@@ -50,7 +50,6 @@ def requirements():
       "blosc",
     ],
     ':sys_platform!="win32"': [
-      "posix_ipc>=1.0.4",
       "psutil>=5.4.3",
     ],
     "mesh_viewer": [ 'vtk' ],