diff --git a/include/vcpkg/base/message-data.inc.h b/include/vcpkg/base/message-data.inc.h
index c8935f471c..de1f374d8c 100644
--- a/include/vcpkg/base/message-data.inc.h
+++ b/include/vcpkg/base/message-data.inc.h
@@ -1129,6 +1129,13 @@ DECLARE_MESSAGE(HashFileFailureToRead,
                 (msg::path),
                 "Printed after ErrorMessage and before the specific failing filesystem operation (like file not found)",
                 "failed to read file \"{path}\" for hashing: ")
+DECLARE_MESSAGE(
+    HashPortManyFiles,
+    (msg::package_name, msg::count),
+    "",
+    "The {package_name} contains a {count} files. Hashing these contents may take a long time when determining the ABI "
+    "hash for binary caching. You should probably consider reducing the number of files. Common causes of this are "
+    "accidentally checking out source or build trees into a port's directory.")
 DECLARE_MESSAGE(HeaderOnlyUsage,
                 (msg::package_name),
                 "'header' refers to C/C++ .h files",
diff --git a/locales/messages.json b/locales/messages.json
index 2ddd2ad790..58e0479cbb 100644
--- a/locales/messages.json
+++ b/locales/messages.json
@@ -711,6 +711,8 @@
   "_GraphCycleDetected.comment": "A list of package names comprising the cycle will be printed after this message. An example of {package_name} is zlib.",
   "HashFileFailureToRead": "failed to read file \"{path}\" for hashing: ",
   "_HashFileFailureToRead.comment": "Printed after ErrorMessage and before the specific failing filesystem operation (like file not found) An example of {path} is /foo/bar.",
+  "HashPortManyFiles": "The {package_name} contains a {count} files. Hashing these contents may take a long time when determining the ABI hash for binary caching. You should probably consider reducing the number of files. Common causes of this are accidentally checking out source or build trees into a port's directory.",
+  "_HashPortManyFiles.comment": "An example of {package_name} is zlib. An example of {count} is 42.",
   "HeaderOnlyUsage": "{package_name} is header-only and can be used from CMake via:",
   "_HeaderOnlyUsage.comment": "'header' refers to C/C++ .h files An example of {package_name} is zlib.",
   "HelpAssetCaching": "**Experimental feature: this may change or be removed at any time**\n\nvcpkg can use mirrors to cache downloaded assets, ensuring continued operation even if the original source changes or disappears.\n\nAsset caching can be configured either by setting the environment variable X_VCPKG_ASSET_SOURCES to a semicolon-delimited list of sources or by passing a sequence of --x-asset-sources=<source> command line options. Command line sources are interpreted after environment sources. Commas, semicolons, and backticks can be escaped using backtick (`).\n\nThe <rw> optional parameter for certain strings controls how they will be accessed. It can be specified as \"read\", \"write\", or \"readwrite\" and defaults to \"read\".\n\nValid sources:",
diff --git a/src/vcpkg/commands.build.cpp b/src/vcpkg/commands.build.cpp
index 409a950739..ba61e12abd 100644
--- a/src/vcpkg/commands.build.cpp
+++ b/src/vcpkg/commands.build.cpp
@@ -1138,17 +1138,22 @@ namespace vcpkg
         abi_entries_from_abi_info(fs, grdk_cache, abi_info, abi_tag_entries);
 
         // If there is an unusually large number of files in the port then
-        // something suspicious is going on.  Rather than hash all of them
-        // just mark the port as no-hash
+        // something suspicious is going on.
         constexpr int max_port_file_count = 100;
 
         std::string portfile_cmake_contents;
         std::vector<Path> files;
         std::vector<std::string> hashes;
         auto&& port_dir = action.source_control_file_and_location.value_or_exit(VCPKG_LINE_INFO).source_location;
-        size_t port_file_count = 0;
         Path abs_port_file;
-        for (auto& port_file : fs.get_regular_files_recursive_lexically_proximate(port_dir, VCPKG_LINE_INFO))
+        auto port_files = fs.get_regular_files_recursive_lexically_proximate(port_dir, VCPKG_LINE_INFO);
+        if (port_files.size() > max_port_file_count)
+        {
+            msg::println_warning(
+                msgHashPortManyFiles, msg::package_name = action.spec.name(), msg::count = port_files.size());
+        }
+
+        for (auto& port_file : port_files)
         {
             if (port_file.filename() == ".DS_Store")
             {
@@ -1167,13 +1172,6 @@ namespace vcpkg
             abi_tag_entries.emplace_back(port_file, hash);
             files.push_back(port_file);
             hashes.push_back(std::move(hash));
-
-            ++port_file_count;
-            if (port_file_count > max_port_file_count)
-            {
-                abi_tag_entries.emplace_back("no_hash_max_portfile", "");
-                break;
-            }
         }
 
         abi_tag_entries.emplace_back("cmake", paths.get_tool_version(Tools::CMAKE, stdout_sink));