diff --git a/src/OrcaSlicer.cpp b/src/OrcaSlicer.cpp
index b75c653eda..24f218caa5 100644
--- a/src/OrcaSlicer.cpp
+++ b/src/OrcaSlicer.cpp
@@ -7715,6 +7715,13 @@ bool CLI::setup(int argc, char **argv)
         this->print_help();
         return false;
     }
+
+    // Orca: resolve here, while the process is still in the directory the user invoked it from.
+    // GUI_App's constructor moves the working directory to <data_dir>/log, long before the GUI
+    // opens these files in post_init(), and a relative path would then resolve against that.
+    for (std::string &input_file : m_input_files)
+        input_file = resolve_cli_input_path(input_file);
+
     // Parse actions and transform options.
     for (auto const &opt_key : opt_order) {
         if (cli_actions_config_def.has(opt_key))
diff --git a/src/libslic3r/Utils.hpp b/src/libslic3r/Utils.hpp
index c364860531..b21da72fc8 100644
--- a/src/libslic3r/Utils.hpp
+++ b/src/libslic3r/Utils.hpp
@@ -314,6 +314,9 @@ extern unsigned get_current_pid();
 std::string per_user_temp_id();
 // Per-user temp root under `base`; an empty `user_id` returns `base` unchanged.
 std::string per_user_temp_dir(const std::string &base, const std::string &user_id);
+// Completes a relative command line input path against the current working directory. Absolute
+// paths and custom open protocol URLs are returned unchanged.
+std::string resolve_cli_input_path(const std::string &path);
 // BBS: backup & restore
 std::string get_process_name(int pid);
 
diff --git a/src/libslic3r/utils.cpp b/src/libslic3r/utils.cpp
index 58323b29ce..9def5dad17 100644
--- a/src/libslic3r/utils.cpp
+++ b/src/libslic3r/utils.cpp
@@ -1339,6 +1339,19 @@ std::string per_user_temp_dir(const std::string &base, const std::string &user_i
     return base + "/orcaslicer_" + user_id;
 }
 
+std::string resolve_cli_input_path(const std::string &path)
+{
+    const boost::filesystem::path input(path);
+    if (path.empty() || is_supported_open_protocol(path) || input.is_absolute())
+        return path;
+
+    boost::system::error_code ec;
+    const boost::filesystem::path resolved = boost::filesystem::system_complete(input, ec);
+    if (ec)
+        return path;
+    return resolved.lexically_normal().make_preferred().string();
+}
+
 // BBS: backup & restore
 std::string get_process_name(int pid)
 {
diff --git a/tests/libslic3r/test_utils.cpp b/tests/libslic3r/test_utils.cpp
index 484438127c..7880b783f1 100644
--- a/tests/libslic3r/test_utils.cpp
+++ b/tests/libslic3r/test_utils.cpp
@@ -4,6 +4,8 @@
 
 #include "test_utils.hpp"
 
+#include <boost/filesystem.hpp>
+
 #include <algorithm>
 #include <cctype>
 #include <fstream>
@@ -88,3 +90,65 @@ TEST_CASE("copy_file reports the OS error when the destination cannot be written
     REQUIRE(std::all_of(code.begin(), code.end(), [](unsigned char c) { return std::isdigit(c) != 0; }));
 #endif // _WIN32
 }
+
+TEST_CASE("A resolved input path still names the same file after the working directory changes", "[utils]") {
+    ScopedTemporaryFile model(".3mf");
+    { std::ofstream out(model.string()); out << "3mf"; }
+    const std::string name = model.path().filename().string();
+
+    // Resolve the bare name from the directory holding the file, then move away from it. The guard
+    // restores the directory the test started in, wherever this leaves it.
+    ScopedWorkingDirectory cwd(model.path().parent_path());
+    const std::string resolved = resolve_cli_input_path(name);
+    boost::filesystem::current_path(boost::filesystem::path(TEST_DATA_DIR));
+
+    REQUIRE(boost::filesystem::exists(resolved));
+    REQUIRE(boost::filesystem::equivalent(resolved, model.path()));
+    // Control: the bare name finds nothing from here, so resolving it this late would have failed.
+    REQUIRE_FALSE(boost::filesystem::exists(name));
+}
+
+TEST_CASE("resolve_cli_input_path completes a relative path against the working directory", "[utils]") {
+    ScopedWorkingDirectory cwd(boost::filesystem::temp_directory_path());
+    // Read back rather than reusing temp_directory_path(): changing to it resolves any symlink.
+    const boost::filesystem::path here = boost::filesystem::current_path();
+
+    SECTION("a bare name") {
+        REQUIRE(resolve_cli_input_path("model.3mf") == (here / "model.3mf").make_preferred().string());
+    }
+    SECTION("a ./ prefix is dropped") {
+        REQUIRE(resolve_cli_input_path("./model.3mf") == (here / "model.3mf").make_preferred().string());
+    }
+    SECTION("a ../ traversal is collapsed") {
+        REQUIRE(resolve_cli_input_path("../model.3mf") == (here.parent_path() / "model.3mf").make_preferred().string());
+    }
+}
+
+TEST_CASE("resolve_cli_input_path leaves inputs that must not be completed unchanged", "[utils]") {
+    SECTION("an absolute path") {
+        const boost::filesystem::path absolute = (boost::filesystem::temp_directory_path() / "model.3mf").make_preferred();
+        REQUIRE(resolve_cli_input_path(absolute.string()) == absolute.string());
+    }
+#ifdef _WIN32
+    // Every absolute form Windows accepts opens today, so each must come back byte for byte:
+    // normalizing them would rewrite the forward slashes and rebuild the \\?\ and UNC prefixes.
+    SECTION("an absolute Windows path of any form") {
+        for (const std::string absolute : {R"(C:\models\model.3mf)",
+                                           R"(C:/models/model.3mf)",
+                                           R"(\\server\share\model.3mf)",
+                                           R"(\\?\C:\models\model.3mf)"})
+            REQUIRE(resolve_cli_input_path(absolute) == absolute);
+    }
+#endif
+    // These are downloaded rather than opened, and completing one would produce a path, not a URL.
+    SECTION("a custom open protocol URL") {
+        for (const std::string url : {"orcaslicer://open/?file=https://example.com/model.3mf",
+                                      "prusaslicer://open/?file=https://example.com/model.3mf",
+                                      "bambustudio://open/?file=https://example.com/model.3mf",
+                                      "cura://open/?file=https://example.com/model.3mf"})
+            REQUIRE(resolve_cli_input_path(url) == url);
+    }
+    SECTION("an empty argument") {
+        REQUIRE(resolve_cli_input_path("").empty());
+    }
+}
diff --git a/tests/test_utils.hpp b/tests/test_utils.hpp
index e3fbbe8fab..0b04e6ad11 100644
--- a/tests/test_utils.hpp
+++ b/tests/test_utils.hpp
@@ -176,4 +176,22 @@ inline void write_debug_stream([[maybe_unused]] const std::string &name, [[maybe
 #endif
 }
 
+// Changes the working directory and restores the previous one on scope exit, including when an
+// assertion throws. It is process wide state shared with every other test.
+class ScopedWorkingDirectory
+{
+public:
+    explicit ScopedWorkingDirectory(const boost::filesystem::path &dir)
+        : m_previous(boost::filesystem::current_path())
+    {
+        boost::filesystem::current_path(dir);
+    }
+    ~ScopedWorkingDirectory() { boost::system::error_code ec; boost::filesystem::current_path(m_previous, ec); }
+    ScopedWorkingDirectory(const ScopedWorkingDirectory &) = delete;
+    ScopedWorkingDirectory &operator=(const ScopedWorkingDirectory &) = delete;
+
+private:
+    boost::filesystem::path m_previous;
+};
+
 #endif // SLIC3R_TEST_UTILS