diff --git a/Userland/DevTools/UserspaceEmulator/Emulator.cpp b/Userland/DevTools/UserspaceEmulator/Emulator.cpp
index 7c0cb551bb..a094621550 100644
--- a/Userland/DevTools/UserspaceEmulator/Emulator.cpp
+++ b/Userland/DevTools/UserspaceEmulator/Emulator.cpp
@@ -9,7 +9,6 @@
 #include "MmapRegion.h"
 #include "SimpleRegion.h"
 #include "SoftCPU.h"
-#include <AK/FileStream.h>
 #include <AK/Format.h>
 #include <AK/LexicalPath.h>
 #include <AK/StringUtils.h>
@@ -501,7 +500,7 @@ void Emulator::dump_backtrace()
     dump_backtrace(raw_backtrace());
 }
 
-void Emulator::emit_profile_sample(AK::OutputStream& output)
+void Emulator::emit_profile_sample(Core::Stream::Stream& output)
 {
     if (!is_in_region_of_interest())
         return;
@@ -511,17 +510,17 @@ void Emulator::emit_profile_sample(AK::OutputStream& output)
     builder.appendff(R"~(, {{"type": "sample", "pid": {}, "tid": {}, "timestamp": {}, "lost_samples": 0, "stack": [)~", getpid(), gettid(), tv.tv_sec * 1000 + tv.tv_usec / 1000);
     builder.join(',', raw_backtrace());
     builder.append("]}\n"sv);
-    output.write_or_error(builder.string_view().bytes());
+    output.write_entire_buffer(builder.string_view().bytes()).release_value_but_fixme_should_propagate_errors();
 }
 
-void Emulator::emit_profile_event(AK::OutputStream& output, StringView event_name, DeprecatedString const& contents)
+void Emulator::emit_profile_event(Core::Stream::Stream& output, StringView event_name, DeprecatedString const& contents)
 {
     StringBuilder builder;
     timeval tv {};
     gettimeofday(&tv, nullptr);
     builder.appendff(R"~(, {{"type": "{}", "pid": {}, "tid": {}, "timestamp": {}, "lost_samples": 0, "stack": [], {}}})~", event_name, getpid(), gettid(), tv.tv_sec * 1000 + tv.tv_usec / 1000, contents);
     builder.append('\n');
-    output.write_or_error(builder.string_view().bytes());
+    output.write_entire_buffer(builder.string_view().bytes()).release_value_but_fixme_should_propagate_errors();
 }
 
 DeprecatedString Emulator::create_instruction_line(FlatPtr address, X86::Instruction const& insn)
diff --git a/Userland/DevTools/UserspaceEmulator/Emulator.h b/Userland/DevTools/UserspaceEmulator/Emulator.h
index 3ba4225ec2..4bb731a70e 100644
--- a/Userland/DevTools/UserspaceEmulator/Emulator.h
+++ b/Userland/DevTools/UserspaceEmulator/Emulator.h
@@ -11,7 +11,6 @@
 #include "RangeAllocator.h"
 #include "Report.h"
 #include "SoftMMU.h"
-#include <AK/FileStream.h>
 #include <AK/Types.h>
 #include <LibCore/MappedFile.h>
 #include <LibDebug/DebugInfo.h>
@@ -33,7 +32,7 @@ public:
 
     Emulator(DeprecatedString const& executable_path, Vector<StringView> const& arguments, Vector<DeprecatedString> const& environment);
 
-    void set_profiling_details(bool should_dump_profile, size_t instruction_interval, OutputFileStream* profile_stream, NonnullOwnPtrVector<DeprecatedString>* profiler_strings, Vector<int>* profiler_string_id_map)
+    void set_profiling_details(bool should_dump_profile, size_t instruction_interval, Core::Stream::Stream* profile_stream, NonnullOwnPtrVector<DeprecatedString>* profiler_strings, Vector<int>* profiler_string_id_map)
     {
         m_is_profiling = should_dump_profile;
         m_profile_instruction_interval = instruction_interval;
@@ -47,7 +46,7 @@ public:
         m_is_in_region_of_interest = value;
     }
 
-    OutputFileStream& profile_stream() { return *m_profile_stream; }
+    Core::Stream::Stream& profile_stream() { return *m_profile_stream; }
     NonnullOwnPtrVector<DeprecatedString>& profiler_strings() { return *m_profiler_strings; }
     Vector<int>& profiler_string_id_map() { return *m_profiler_string_id_map; }
 
@@ -140,8 +139,8 @@ private:
 
     void send_signal(int);
 
-    void emit_profile_sample(AK::OutputStream&);
-    void emit_profile_event(AK::OutputStream&, StringView event_name, DeprecatedString const& contents);
+    void emit_profile_sample(Core::Stream::Stream&);
+    void emit_profile_event(Core::Stream::Stream&, StringView event_name, DeprecatedString const& contents);
 
     int virt$accept4(FlatPtr);
     u32 virt$allocate_tls(FlatPtr, size_t);
@@ -296,7 +295,7 @@ private:
 
     RangeAllocator m_range_allocator;
 
-    OutputFileStream* m_profile_stream { nullptr };
+    Core::Stream::Stream* m_profile_stream { nullptr };
     Vector<int>* m_profiler_string_id_map { nullptr };
     NonnullOwnPtrVector<DeprecatedString>* m_profiler_strings { nullptr };
 
diff --git a/Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp b/Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp
index f4dbe20730..93909afc52 100644
--- a/Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp
+++ b/Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp
@@ -10,7 +10,6 @@
 #include "SimpleRegion.h"
 #include "SoftCPU.h"
 #include <AK/Debug.h>
-#include <AK/FileStream.h>
 #include <AK/Format.h>
 #include <Kernel/API/SyscallString.h>
 #include <alloca.h>
diff --git a/Userland/DevTools/UserspaceEmulator/main.cpp b/Userland/DevTools/UserspaceEmulator/main.cpp
index f62b1f2b2a..181699e0ce 100644
--- a/Userland/DevTools/UserspaceEmulator/main.cpp
+++ b/Userland/DevTools/UserspaceEmulator/main.cpp
@@ -5,7 +5,6 @@
  */
 
 #include "Emulator.h"
-#include <AK/FileStream.h>
 #include <AK/Format.h>
 #include <AK/LexicalPath.h>
 #include <AK/StringBuilder.h>
@@ -24,7 +23,6 @@ int main(int argc, char** argv, char** env)
     Vector<StringView> arguments;
     bool pause_on_startup { false };
     DeprecatedString profile_dump_path;
-    FILE* profile_output_file { nullptr };
     bool enable_roi_mode { false };
     bool dump_profile { false };
     unsigned profile_instruction_interval { 0 };
@@ -58,29 +56,29 @@ int main(int argc, char** argv, char** env)
     if (dump_profile && profile_dump_path.is_empty())
         profile_dump_path = DeprecatedString::formatted("{}.{}.profile", LexicalPath(executable_path).basename(), getpid());
 
-    OwnPtr<OutputFileStream> profile_stream;
+    OwnPtr<Core::Stream::Stream> profile_stream;
     OwnPtr<NonnullOwnPtrVector<DeprecatedString>> profile_strings;
     OwnPtr<Vector<int>> profile_string_id_map;
 
     if (dump_profile) {
-        profile_output_file = fopen(profile_dump_path.characters(), "w+");
-        if (profile_output_file == nullptr) {
-            char const* error_string = strerror(errno);
-            warnln("Failed to open '{}' for writing: {}", profile_dump_path, error_string);
+        auto profile_stream_or_error = Core::Stream::File::open(profile_dump_path, Core::Stream::OpenMode::Write);
+        if (profile_stream_or_error.is_error()) {
+            warnln("Failed to open '{}' for writing: {}", profile_dump_path, profile_stream_or_error.error());
             return 1;
         }
-        profile_stream = make<OutputFileStream>(profile_output_file);
+        profile_stream = profile_stream_or_error.release_value();
         profile_strings = make<NonnullOwnPtrVector<DeprecatedString>>();
         profile_string_id_map = make<Vector<int>>();
 
-        profile_stream->write_or_error(R"({"events":[)"sv.bytes());
+        profile_stream->write_entire_buffer(R"({"events":[)"sv.bytes()).release_value_but_fixme_should_propagate_errors();
         timeval tv {};
         gettimeofday(&tv, nullptr);
-        profile_stream->write_or_error(
-            DeprecatedString::formatted(
-                R"~({{"type": "process_create", "parent_pid": 1, "executable": "{}", "pid": {}, "tid": {}, "timestamp": {}, "lost_samples": 0, "stack": []}})~",
-                executable_path, getpid(), gettid(), tv.tv_sec * 1000 + tv.tv_usec / 1000)
-                .bytes());
+        profile_stream->write_entire_buffer(
+                          DeprecatedString::formatted(
+                              R"~({{"type": "process_create", "parent_pid": 1, "executable": "{}", "pid": {}, "tid": {}, "timestamp": {}, "lost_samples": 0, "stack": []}})~",
+                              executable_path, getpid(), gettid(), tv.tv_sec * 1000 + tv.tv_usec / 1000)
+                              .bytes())
+            .release_value_but_fixme_should_propagate_errors();
     }
 
     Vector<DeprecatedString> environment;
@@ -116,13 +114,13 @@ int main(int argc, char** argv, char** env)
     rc = emulator.exec();
 
     if (dump_profile) {
-        emulator.profile_stream().write_or_error("], \"strings\": ["sv.bytes());
+        emulator.profile_stream().write_entire_buffer("], \"strings\": ["sv.bytes()).release_value_but_fixme_should_propagate_errors();
         if (emulator.profiler_strings().size()) {
             for (size_t i = 0; i < emulator.profiler_strings().size() - 1; ++i)
-                emulator.profile_stream().write_or_error(DeprecatedString::formatted("\"{}\", ", emulator.profiler_strings().at(i)).bytes());
-            emulator.profile_stream().write_or_error(DeprecatedString::formatted("\"{}\"", emulator.profiler_strings().last()).bytes());
+                emulator.profile_stream().write_entire_buffer(DeprecatedString::formatted("\"{}\", ", emulator.profiler_strings().at(i)).bytes()).release_value_but_fixme_should_propagate_errors();
+            emulator.profile_stream().write_entire_buffer(DeprecatedString::formatted("\"{}\"", emulator.profiler_strings().last()).bytes()).release_value_but_fixme_should_propagate_errors();
         }
-        emulator.profile_stream().write_or_error("]}"sv.bytes());
+        emulator.profile_stream().write_entire_buffer("]}"sv.bytes()).release_value_but_fixme_should_propagate_errors();
     }
     return rc;
 }