diff --git a/volatility/framework/automagic/linux.py b/volatility/framework/automagic/linux.py
index 3cff98b12..56fb7ccfb 100644
--- a/volatility/framework/automagic/linux.py
+++ b/volatility/framework/automagic/linux.py
@@ -66,6 +66,11 @@ class LintelStacker(interfaces.automagic.StackerLayerInterface):
             return None
 
         linux_banners = LinuxBannerCache.load_banners()
+        # If we have no banners, don't bother scanning
+        if not linux_banners:
+            vollog.info("No Linux banners found - if this is a linux plugin, please check your symbol files location")
+            return None
+
         mss = scanners.MultiStringScanner([x for x in linux_banners if x is not None])
         for _, banner in layer.scan(context = context, scanner = mss, progress_callback = progress_callback):
             dtb = None
diff --git a/volatility/framework/automagic/mac.py b/volatility/framework/automagic/mac.py
index 7eeac10a6..ff00eae64 100644
--- a/volatility/framework/automagic/mac.py
+++ b/volatility/framework/automagic/mac.py
@@ -20,7 +20,7 @@
 
 import logging
 import struct
-from typing import Optional, Tuple
+from typing import Optional
 
 from volatility.framework import interfaces, constants, validity, layers
 from volatility.framework import symbols
@@ -66,11 +66,14 @@ class MacintelStacker(interfaces.automagic.StackerLayerInterface):
             return None
 
         mac_banners = MacBannerCache.load_banners()
+        # If we have no banners, don't bother scanning
+        if not mac_banners:
+            vollog.info("No Mac banners found - if this is a mac plugin, please check your symbol files location")
+            return None
 
+        mss = scanners.MultiStringScanner([x for x in mac_banners if x])
         for banner_offset, banner in layer.scan(
-                context = context,
-                scanner = scanners.MultiStringScanner([x for x in mac_banners if x]),
-                progress_callback = progress_callback):
+                context = context, scanner = mss, progress_callback = progress_callback):
             dtb = None
             vollog.debug("Identified banner: {}".format(repr(banner)))
 
diff --git a/volatility/framework/automagic/symbol_cache.py b/volatility/framework/automagic/symbol_cache.py
index 0784f8922..14ee06741 100644
--- a/volatility/framework/automagic/symbol_cache.py
+++ b/volatility/framework/automagic/symbol_cache.py
@@ -17,7 +17,7 @@
 # WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
 # specific language governing rights and limitations under the License.
 #
-
+import gc
 import logging
 import os
 import pickle
@@ -109,6 +109,7 @@ class SymbolBannerCache(interfaces.automagic.AutomagicInterface):
             progress_callback(current * 100 / total, "Building {} caches".format(self.os))
             isf_url = cacheables[current]
 
+            isf = None
             try:
                 # Loading the symbol table will be very slow until it's been validated
                 isf = intermed.IntermediateSymbolTable(context, config_path, "temp", isf_url, validate = False)
@@ -118,11 +119,17 @@ class SymbolBannerCache(interfaces.automagic.AutomagicInterface):
                 # but we should check at least that the banner matches on load.
                 banner = isf.get_symbol(self.symbol_name).constant_data
                 vollog.log(constants.LOGLEVEL_V, "Caching banner {} for file {}".format(banner, isf_url))
+
                 bannerlist = banners.get(banner, [])
                 bannerlist.append(isf_url)
                 banners[banner] = bannerlist
             except exceptions.SymbolError:
                 pass
+            finally:
+                # Get rid of the loaded file, in case it sits in memory
+                if isf:
+                    del isf
+                    gc.collect()
 
             # Rewrite the cached banners each run, since writing is faster than the banner_cache validation portion
             self.save_banners(banners)
diff --git a/volatility/framework/layers/scanners/multiregexp.py b/volatility/framework/layers/scanners/multiregexp.py
index 7d8e42176..6e38ecbdc 100644
--- a/volatility/framework/layers/scanners/multiregexp.py
+++ b/volatility/framework/layers/scanners/multiregexp.py
@@ -39,6 +39,8 @@ class MultiRegexp(object):
             -> Generator[Tuple[int, Union[str, bytes]], None, None]:
         if not isinstance(haystack, bytes):
             raise TypeError("Search haystack must be a byte string")
+        if not self._regex:
+            raise ValueError("MultiRegexp cannot be used with an empty set of search strings")
         for match in re.finditer(self._regex, haystack):
             yield (match.start(0), match.group())