diff --git a/Configuration/src/main/java/io/deephaven/configuration/DataDir.java b/Configuration/src/main/java/io/deephaven/configuration/DataDir.java
index 9dfedce05cd..308501a763d 100644
--- a/Configuration/src/main/java/io/deephaven/configuration/DataDir.java
+++ b/Configuration/src/main/java/io/deephaven/configuration/DataDir.java
@@ -12,6 +12,7 @@ public class DataDir {
     @Deprecated
     private static final String WORKSPACE_PROPERTY = "workspace";
     public static final String ENV_VAR = "DEEPHAVEN_DATA_DIR";
+    public static final String WINDOWS_SEPARATOR = "\\";
 
     private static final String DEFAULT_DATA_DIR = ".";
 
diff --git a/server/src/main/java/io/deephaven/server/notebook/FilesystemStorageServiceGrpcImpl.java b/server/src/main/java/io/deephaven/server/notebook/FilesystemStorageServiceGrpcImpl.java
old mode 100644
new mode 100755
index ee60bdfd0e6..b2603e5c852
--- a/server/src/main/java/io/deephaven/server/notebook/FilesystemStorageServiceGrpcImpl.java
+++ b/server/src/main/java/io/deephaven/server/notebook/FilesystemStorageServiceGrpcImpl.java
@@ -10,7 +10,6 @@
 import com.google.rpc.Code;
 import io.deephaven.configuration.Configuration;
 import io.deephaven.configuration.DataDir;
-import io.deephaven.extensions.barrage.util.GrpcUtil;
 import io.deephaven.internal.log.LoggerFactory;
 import io.deephaven.io.logger.Logger;
 import io.deephaven.proto.backplane.grpc.CreateDirectoryRequest;
@@ -92,6 +91,11 @@ public class FilesystemStorageServiceGrpcImpl extends StorageServiceGrpc.Storage
      */
     @Deprecated
     private static final String REQUIRED_PATH_PREFIX = "/";
+    /**
+     * Although REQUIRED_PATH_PREFIX has been deprecated, it is still used; this constant is for the same forward slash,
+     * to detect situations where the UI path separator is different from the OS path separator (i.e. on Windows).
+     */
+    private static final String LINUX_SEPARATOR = "/";
 
     private final Path root = Paths.get(STORAGE_PATH).normalize();
     private final SessionService sessionService;
@@ -114,14 +118,19 @@ public FilesystemStorageServiceGrpcImpl(
     }
 
     private Path resolveOrThrow(String incomingPath) {
-        if (incomingPath.startsWith(File.separator)) {
+        String resolveDetails = "\nOriginal incoming path is: " + incomingPath;
+        resolveDetails = resolveDetails + "\nFile separator is: " + File.separator;
+        incomingPath = maybeReplaceFileSeparators(incomingPath);
+        while (incomingPath.startsWith(REQUIRED_PATH_PREFIX)) {
             incomingPath = incomingPath.substring(1);
         }
         Path resolved = root.resolve(incomingPath).normalize();
+
         if (resolved.startsWith(root)) {
             return resolved;
         }
-        throw Exceptions.statusRuntimeException(Code.INVALID_ARGUMENT, "Invalid path: " + incomingPath);
+        throw Exceptions.statusRuntimeException(Code.INVALID_ARGUMENT, "Invalid path: " + incomingPath
+                + "." + resolveDetails);
     }
 
     private void requireNotRoot(Path path, String message) {
@@ -130,6 +139,20 @@ private void requireNotRoot(Path path, String message) {
         }
     }
 
+    /**
+     * On Windows systems, we need to replace backslashes with forward slashes for the Web UI
+     * 
+     * @param path Path String that may need to be modified
+     * @return Original path on non-Windows systems, or path with backslashes replaced with slashes on Windows systems.
+     */
+    private String maybeReplaceFileSeparators(final String path) {
+        if (File.separator.equals(DataDir.WINDOWS_SEPARATOR)) {
+            return path.replace(DataDir.WINDOWS_SEPARATOR, LINUX_SEPARATOR);
+        } else {
+            return path;
+        }
+    }
+
     @Override
     public void listItems(
             @NotNull final ListItemsRequest request,
@@ -148,8 +171,9 @@ public void listItems(
                 }
                 BasicFileAttributes attrs = Files.readAttributes(p, BasicFileAttributes.class);
                 boolean isDirectory = attrs.isDirectory();
+                String relativePath = maybeReplaceFileSeparators(root.relativize(p).toString());
                 ItemInfo.Builder info = ItemInfo.newBuilder()
-                        .setPath(REQUIRED_PATH_PREFIX + root.relativize(p));
+                        .setPath(REQUIRED_PATH_PREFIX + relativePath);
                 if (isDirectory) {
                     info.setType(ItemType.DIRECTORY);
                 } else {
@@ -172,7 +196,7 @@ private static PathMatcher createPathFilter(String filterGlob) {
         if (filterGlob.contains("**")) {
             throw Exceptions.statusRuntimeException(Code.INVALID_ARGUMENT, "Bad glob, only single `*`s are supported");
         }
-        if (filterGlob.contains(File.separator)) {
+        if (filterGlob.contains(File.separator) || filterGlob.contains(LINUX_SEPARATOR)) {
             throw Exceptions.statusRuntimeException(Code.INVALID_ARGUMENT,
                     "Bad glob, only the same directory can be checked");
         }
diff --git a/server/src/main/java/io/deephaven/server/runner/MainHelper.java b/server/src/main/java/io/deephaven/server/runner/MainHelper.java
index 9146b3782e2..5bd2eb5cb5d 100644
--- a/server/src/main/java/io/deephaven/server/runner/MainHelper.java
+++ b/server/src/main/java/io/deephaven/server/runner/MainHelper.java
@@ -25,7 +25,7 @@
 import io.deephaven.util.process.ProcessEnvironment;
 import org.jetbrains.annotations.NotNull;
 import org.slf4j.bridge.SLF4JBridgeHandler;
-
+import java.io.File;
 import java.io.IOException;
 import java.io.Reader;
 import java.nio.charset.Charset;
@@ -63,6 +63,14 @@ private static void bootstrapFromFile(Path configFile) throws IOException {
         }
     }
 
+    // Spaces in the paths are tedious on Windows
+    private static String maybeRemoveSpaces(final String pathToCheck) {
+        if (pathToCheck == null) {
+            return null;
+        }
+        return (File.separator.equals(DataDir.WINDOWS_SEPARATOR)) ? pathToCheck.replace(" ", "") : pathToCheck;
+    }
+
     @VisibleForTesting
     public static void bootstrapProjectDirectories() throws IOException {
         final String applicationName =
@@ -72,9 +80,9 @@ public static void bootstrapProjectDirectories() throws IOException {
         final dev.dirs.ProjectDirectories defaultDirectories =
                 dev.dirs.ProjectDirectories.from("io", "Deephaven Data Labs", applicationName);
 
-        final Path cacheDir = CacheDir.getOrSet(defaultDirectories.cacheDir);
-        final Path configDir = ConfigDir.getOrSet(defaultDirectories.configDir);
-        final Path dataDir = DataDir.getOrSet(defaultDirectories.dataDir);
+        final Path cacheDir = CacheDir.getOrSet(maybeRemoveSpaces(defaultDirectories.cacheDir));
+        final Path configDir = ConfigDir.getOrSet(maybeRemoveSpaces(defaultDirectories.configDir));
+        final Path dataDir = DataDir.getOrSet(maybeRemoveSpaces(defaultDirectories.dataDir));
 
         Files.createDirectories(cacheDir);
         Files.createDirectories(dataDir);