diff --git a/src/pysme/atmosphere/savfile.py b/src/pysme/atmosphere/savfile.py
index fadba8aa..d4fef44d 100644
--- a/src/pysme/atmosphere/savfile.py
+++ b/src/pysme/atmosphere/savfile.py
@@ -1,3 +1,4 @@
+import os
 from os.path import basename
 from tempfile import NamedTemporaryFile
 
@@ -147,9 +148,20 @@ def __new__(cls, filename, source=None, lfs=None):
         # Store in cache
         cls._cache = self
         # And also replace the IDL file with a numpy file in the cache
+        # We have to use a try except block, as this will crash with
+        # permissions denied on windows, when trying to copy an open file
+        # here the temporary file
+        # Therefore we close the file, after copying and then delete it manually
         if lfs is not None:
-            with NamedTemporaryFile() as named:
-                self.save(named)
+            try:
+                with NamedTemporaryFile(delete=False) as named:
+                    self.save(named)
+                    named.flush()
                 lfs.move_to_cache(named.name, key=lfs.get_url(self.source))
+            finally:
+                try:
+                    os.remove(named.name)
+                except:
+                    pass
 
         return self
diff --git a/src/pysme/large_file_storage.py b/src/pysme/large_file_storage.py
index b7fdd955..a76ac01c 100644
--- a/src/pysme/large_file_storage.py
+++ b/src/pysme/large_file_storage.py
@@ -11,7 +11,7 @@
 import json
 import logging
 import os
-from os.path import basename, join
+from os.path import basename
 from pathlib import Path
 from tempfile import NamedTemporaryFile
 
@@ -102,24 +102,34 @@ def get(self, key):
     def _unpack(self, fname, key, url):
         logger.debug("Unpacking data file %s", key)
 
-        with gzip.open(fname, "rb") as f_in:
-            with NamedTemporaryFile("wb") as f_out:
-                with tqdm(
-                    # total=f_in.size,
-                    desc="Unpack",
-                    unit="B",
-                    unit_scale=True,
-                    unit_divisor=1024,
-                ) as t:
-                    fobj = CallbackIOWrapper(t.update, f_in, "read")
-                    while True:
-                        chunk = fobj.read(1024)
-                        if not chunk:
-                            break
-                        f_out.write(chunk)
-                    f_out.flush()
-                    t.reset()
-                import_file_to_cache(url, f_out.name, pkgname="pysme")
+        # We have to use a try except block, as this will crash with
+        # permissions denied on windows, when trying to copy an open file
+        # here the temporary file
+        # Therefore we close the file, after copying and then delete it manually
+        try:
+            with gzip.open(fname, "rb") as f_in:
+                with NamedTemporaryFile("wb", delete=False) as f_out:
+                    with tqdm(
+                        # total=f_in.size,
+                        desc="Unpack",
+                        unit="B",
+                        unit_scale=True,
+                        unit_divisor=1024,
+                    ) as t:
+                        fobj = CallbackIOWrapper(t.update, f_in, "read")
+                        while True:
+                            chunk = fobj.read(1024)
+                            if not chunk:
+                                break
+                            f_out.write(chunk)
+                        f_out.flush()
+                        t.reset()
+            import_file_to_cache(url, f_out.name, pkgname="pysme")
+        finally:
+            try:
+                os.remove(f_out.name)
+            except:
+                pass
 
     def get_url(self, key):
         key = str(key)
@@ -132,13 +142,13 @@ def get_url(self, key):
                         f"File {key} does not exist and is not tracked by the Large File system"
                     )
                 else:
-                    return str(key)
+                    return Path(key).as_uri()
             else:
-                return str(self.current / key)
+                return (self.current / key).as_uri()
 
         # Otherwise get it from the cache or online if necessary
         newest = self.pointers[key]
-        url = join(self.server, newest)
+        url = self.server + "/" + newest
         return url
 
     def clean_cache(self):
diff --git a/src/pysme/libtools.py b/src/pysme/libtools.py
index 8a83652a..e59af2da 100644
--- a/src/pysme/libtools.py
+++ b/src/pysme/libtools.py
@@ -91,6 +91,6 @@ def load_library(libfile=None):
 
 
 def get_full_datadir():
-    localdir = realpath(dirname(__file__))
+    localdir = dirname(__file__)
     datadir = join(localdir, "share/libsme/")
     return datadir
diff --git a/src/pysme/sme_synth.py b/src/pysme/sme_synth.py
index 66dbc36d..e0930575 100644
--- a/src/pysme/sme_synth.py
+++ b/src/pysme/sme_synth.py
@@ -1,6 +1,7 @@
 """ Wrapper for sme_synth.so C library """
 import logging
 import os
+from os.path import normpath
 
 import numpy as np
 
@@ -181,6 +182,7 @@ def SetLibraryPath(self, libpath=None):
         """Set the path to the library"""
         if libpath is None:
             libpath = get_full_datadir()
+        libpath = normpath(libpath) + os.sep
         self.lib.SetLibraryPath(libpath, type="string", state=self.state)
 
     def InputWaveRange(self, wfirst, wlast):