diff --git a/src/libs/utils/synchronousprocess.cpp b/src/libs/utils/synchronousprocess.cpp
index fab9f93a030..f15eb449387 100644
--- a/src/libs/utils/synchronousprocess.cpp
+++ b/src/libs/utils/synchronousprocess.cpp
@@ -410,16 +410,6 @@ void SynchronousProcess::setEnvironment(const Environment &e)
     d->m_process.setEnvironment(Environment(e));
 }
 
-void SynchronousProcess::setProcessEnvironment(const QProcessEnvironment &environment)
-{
-    d->m_process.setProcessEnvironment(environment);
-}
-
-QProcessEnvironment SynchronousProcess::processEnvironment() const
-{
-    return d->m_process.processEnvironment();
-}
-
 unsigned SynchronousProcess::flags() const
 {
     return d->m_process.flags();
diff --git a/src/libs/utils/synchronousprocess.h b/src/libs/utils/synchronousprocess.h
index 546ab1b0413..967e6d4456b 100644
--- a/src/libs/utils/synchronousprocess.h
+++ b/src/libs/utils/synchronousprocess.h
@@ -116,9 +116,6 @@ public:
     Environment environment() const;
     void setEnvironment(const Environment &);
 
-    void setProcessEnvironment(const QProcessEnvironment &environment);
-    QProcessEnvironment processEnvironment() const;
-
     void setWorkingDirectory(const QString &workingDirectory);
     QString workingDirectory() const;
 
diff --git a/src/plugins/cmakeprojectmanager/cmakeprojectimporter.cpp b/src/plugins/cmakeprojectmanager/cmakeprojectimporter.cpp
index d83169402c6..3dd759e8192 100644
--- a/src/plugins/cmakeprojectmanager/cmakeprojectimporter.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeprojectimporter.cpp
@@ -203,7 +203,7 @@ static FilePath qmakeFromCMakeCache(const CMakeConfig &config)
     cmake.setFlags(SynchronousProcess::UnixTerminalDisabled);
     Environment env = Environment::systemEnvironment();
     Environment::setupEnglishOutput(&env);
-    cmake.setProcessEnvironment(env.toProcessEnvironment());
+    cmake.setEnvironment(env);
     cmake.setTimeOutMessageBoxEnabled(false);
 
     QString cmakeGenerator
diff --git a/src/plugins/cmakeprojectmanager/cmaketool.cpp b/src/plugins/cmakeprojectmanager/cmaketool.cpp
index 678acdf554f..e6cb1f434c1 100644
--- a/src/plugins/cmakeprojectmanager/cmaketool.cpp
+++ b/src/plugins/cmakeprojectmanager/cmaketool.cpp
@@ -196,7 +196,7 @@ Utils::SynchronousProcessResponse CMakeTool::run(const QStringList &args, int ti
     cmake.setFlags(Utils::SynchronousProcess::UnixTerminalDisabled);
     Utils::Environment env = Utils::Environment::systemEnvironment();
     Utils::Environment::setupEnglishOutput(&env);
-    cmake.setProcessEnvironment(env.toProcessEnvironment());
+    cmake.setEnvironment(env);
     cmake.setTimeOutMessageBoxEnabled(false);
 
     return cmake.runBlocking({cmakeExecutable(), args});
diff --git a/src/plugins/perforce/perforceplugin.cpp b/src/plugins/perforce/perforceplugin.cpp
index c5d89ce0056..b133487ec94 100644
--- a/src/plugins/perforce/perforceplugin.cpp
+++ b/src/plugins/perforce/perforceplugin.cpp
@@ -106,10 +106,10 @@ static inline QStringList perforceRelativeProjectDirectory(const VcsBasePluginSt
 }
 
 // Clean user setting off diff-binary for 'p4 resolve' and 'p4 diff'.
-static inline QProcessEnvironment overrideDiffEnvironmentVariable()
+static Environment overrideDiffEnvironmentVariable()
 {
-    QProcessEnvironment rc = QProcessEnvironment::systemEnvironment();
-    rc.remove(QLatin1String("P4DIFF"));
+    Environment rc = Environment::systemEnvironment();
+    rc.unset("P4DIFF");
     return rc;
 }
 
@@ -1255,7 +1255,7 @@ PerforceResponse PerforcePluginPrivate::synchronousProcess(const QString &workin
     if (outputCodec)
         process.setCodec(outputCodec);
     if (flags & OverrideDiffEnvironment)
-        process.setProcessEnvironment(overrideDiffEnvironmentVariable());
+        process.setEnvironment(overrideDiffEnvironmentVariable());
     if (!workingDir.isEmpty())
         process.setWorkingDirectory(workingDir);
 
@@ -1317,15 +1317,16 @@ PerforceResponse PerforcePluginPrivate::fullySynchronousProcess(const QString &w
                                                                 const QByteArray &stdInput,
                                                                 QTextCodec *outputCodec) const
 {
-    QProcess process;
+    QtcProcess process;
 
     if (flags & OverrideDiffEnvironment)
-        process.setProcessEnvironment(overrideDiffEnvironmentVariable());
+        process.setEnvironment(overrideDiffEnvironmentVariable());
     if (!workingDir.isEmpty())
         process.setWorkingDirectory(workingDir);
 
     PerforceResponse response;
-    process.start(m_settings.p4BinaryPath.value(), args);
+    process.setCommand({m_settings.p4BinaryPath.value(), args});
+    process.start();
     if (stdInput.isEmpty())
         process.closeWriteChannel();
 
@@ -1336,7 +1337,7 @@ PerforceResponse PerforcePluginPrivate::fullySynchronousProcess(const QString &w
     }
     if (!stdInput.isEmpty()) {
         if (process.write(stdInput) == -1) {
-            SynchronousProcess::stopProcess(process);
+            process.stopProcess();
             response.error = true;
             response.message = tr("Unable to write input data to process %1: %2").
                                arg(QDir::toNativeSeparators(m_settings.p4BinaryPath.value()),