diff --git a/src/DBConnection.cpp b/src/DBConnection.cpp
index d0b3b8348..f1b54b170 100644
--- a/src/DBConnection.cpp
+++ b/src/DBConnection.cpp
@@ -55,6 +55,28 @@ bool DBConnection::ShouldBypass()
    return mBypass;
 }
 
+void DBConnection::SetError(
+   const TranslatableString &msg, const TranslatableString &libraryError)
+{
+   mLastError = msg;
+   mLibraryError = libraryError;
+}
+
+void DBConnection::SetDBError(
+   const TranslatableString &msg, const TranslatableString &libraryError)
+{
+   mLastError = msg;
+   wxLogDebug(wxT("SQLite error: %s"), mLastError.Debug());
+   printf("   Lib error: %s", mLastError.Debug().mb_str().data());
+
+   mLibraryError = libraryError.empty()
+      ? Verbatim(sqlite3_errmsg(DB())) : libraryError;
+   wxLogDebug(wxT("   Lib error: %s"), mLibraryError.Debug());
+   printf("   Lib error: %s", mLibraryError.Debug().mb_str().data());
+
+   wxASSERT(false);
+}
+
 bool DBConnection::Open(const char *fileName)
 {
    wxASSERT(mDB == nullptr);
@@ -315,6 +337,107 @@ int DBConnection::CheckpointHook(void *data, sqlite3 *db, const char *schema, in
    return SQLITE_OK;
 }
 
+bool TransactionScope::TransactionStart(const wxString &name)
+{
+   char *errmsg = nullptr;
+
+   int rc = sqlite3_exec(mConnection.DB(),
+                         wxT("SAVEPOINT ") + name + wxT(";"),
+                         nullptr,
+                         nullptr,
+                         &errmsg);
+
+   if (errmsg)
+   {
+      mConnection.SetDBError(
+         XO("Failed to create savepoint:\n\n%s").Format(name)
+      );
+      sqlite3_free(errmsg);
+   }
+
+   return rc == SQLITE_OK;
+}
+
+bool TransactionScope::TransactionCommit(const wxString &name)
+{
+   char *errmsg = nullptr;
+
+   int rc = sqlite3_exec(mConnection.DB(),
+                         wxT("RELEASE ") + name + wxT(";"),
+                         nullptr,
+                         nullptr,
+                         &errmsg);
+
+   if (errmsg)
+   {
+      mConnection.SetDBError(
+         XO("Failed to release savepoint:\n\n%s").Format(name)
+      );
+      sqlite3_free(errmsg);
+   }
+
+   return rc == SQLITE_OK;
+}
+
+bool TransactionScope::TransactionRollback(const wxString &name)
+{
+   char *errmsg = nullptr;
+
+   int rc = sqlite3_exec(mConnection.DB(),
+                         wxT("ROLLBACK TO ") + name + wxT(";"),
+                         nullptr,
+                         nullptr,
+                         &errmsg);
+
+   if (errmsg)
+   {
+      mConnection.SetDBError(
+         XO("Failed to release savepoint:\n\n%s").Format(name)
+      );
+      sqlite3_free(errmsg);
+   }
+
+   return rc == SQLITE_OK;
+}
+
+TransactionScope::TransactionScope(
+   DBConnection &connection, const char *name)
+:  mConnection(connection),
+   mName(name)
+{
+   mInTrans = TransactionStart(mName);
+   if ( !mInTrans )
+      // To do, improve the message
+      throw SimpleMessageBoxException( XO("Database error") );
+}
+
+TransactionScope::~TransactionScope()
+{
+   if (mInTrans)
+   {
+      // Rollback AND REMOVE the transaction
+      // -- must do both; rolling back a savepoint only rewinds it
+      // without removing it, unlike the ROLLBACK command
+      if (!(TransactionRollback(mName) &&
+            TransactionCommit(mName) ) )
+      {
+         // Do not throw from a destructor!
+         // This has to be a no-fail cleanup that does the best that it can.
+      }
+   }
+}
+
+bool TransactionScope::Commit()
+{
+   if ( !mInTrans )
+      // Misuse of this class
+      THROW_INCONSISTENCY_EXCEPTION;
+
+   mInTrans = !TransactionCommit(mName);
+
+   return mInTrans;
+}
+
 ConnectionPtr::~ConnectionPtr()
 {
    wxASSERT_MSG(!mpConnection, wxT("Project file was not closed at shutdown"));
diff --git a/src/DBConnection.h b/src/DBConnection.h
index c208639c3..131b85e8d 100644
--- a/src/DBConnection.h
+++ b/src/DBConnection.h
@@ -69,6 +69,21 @@ public:
    void SetBypass( bool bypass );
    bool ShouldBypass();
 
+   //! Just set stored errors
+   void SetError(
+      const TranslatableString &msg,
+      const TranslatableString &libraryError = {} );
+
+   //! Set stored errors and write to log; and default libraryError to what database library reports
+   void SetDBError(
+      const TranslatableString &msg,
+      const TranslatableString &libraryError = {} );
+
+   const TranslatableString &GetLastError() const
+   { return mLastError; }
+   const TranslatableString &GetLibraryError() const
+   { return mLibraryError; }
+
 private:
    bool ModeConfig(sqlite3 *db, const char *schema, const char *config);
 
@@ -88,10 +103,35 @@ private:
 
    std::map<enum StatementID, sqlite3_stmt *> mStatements;
 
+   TranslatableString mLastError;
+   TranslatableString mLibraryError;
+
    // Bypass transactions if database will be deleted after close
    bool mBypass;
 };
 
+// Make a savepoint (a transaction, possibly nested) with the given name;
+// roll it back at destruction time, unless an explicit Commit() happened first.
+// Commit() must not be called again after one successful call.
+// An exception is thrown from the constructor if the transaction cannot open.
+class TransactionScope
+{
+public:
+   TransactionScope(DBConnection &connection, const char *name);
+   ~TransactionScope();
+
+   bool Commit();
+
+private:
+   bool TransactionStart(const wxString &name);
+   bool TransactionCommit(const wxString &name);
+   bool TransactionRollback(const wxString &name);
+
+   DBConnection &mConnection;
+   bool mInTrans;
+   wxString mName;
+};
+
 using Connection = std::unique_ptr<DBConnection>;
 
 // This object attached to the project simply holds the pointer to the
diff --git a/src/ProjectFileIO.cpp b/src/ProjectFileIO.cpp
index 0ea12f42d..a1b367c51 100644
--- a/src/ProjectFileIO.cpp
+++ b/src/ProjectFileIO.cpp
@@ -256,7 +256,7 @@ ProjectFileIO::~ProjectFileIO()
 {
 }
 
-sqlite3 *ProjectFileIO::DB()
+DBConnection &ProjectFileIO::GetConnection()
 {
    auto &curConn = CurrConn();
    if (!curConn)
@@ -270,9 +270,18 @@ sqlite3 *ProjectFileIO::DB()
       }
    }
 
-   return curConn->DB();
+   return *curConn;
 }
 
+sqlite3 *ProjectFileIO::DB()
+{
+   return GetConnection().DB();
+}
+
+/*!
+ @pre *CurConn() does not exist
+ @post *CurConn() exists or return value is false
+ */
 bool ProjectFileIO::OpenConnection(FilePath fileName /* = {}  */)
 {
    auto &curConn = CurrConn();
@@ -414,69 +423,6 @@ void ProjectFileIO::UseConnection(Connection &&conn, const FilePath &filePath)
    SetFileName(filePath);
 }
 
-bool ProjectFileIO::TransactionStart(const wxString &name)
-{
-   char *errmsg = nullptr;
-
-   int rc = sqlite3_exec(DB(),
-                         wxT("SAVEPOINT ") + name + wxT(";"),
-                         nullptr,
-                         nullptr,
-                         &errmsg);
-
-   if (errmsg)
-   {
-      SetDBError(
-         XO("Failed to create savepoint:\n\n%s").Format(name)
-      );
-      sqlite3_free(errmsg);
-   }
-
-   return rc == SQLITE_OK;
-}
-
-bool ProjectFileIO::TransactionCommit(const wxString &name)
-{
-   char *errmsg = nullptr;
-
-   int rc = sqlite3_exec(DB(),
-                         wxT("RELEASE ") + name + wxT(";"),
-                         nullptr,
-                         nullptr,
-                         &errmsg);
-
-   if (errmsg)
-   {
-      SetDBError(
-         XO("Failed to release savepoint:\n\n%s").Format(name)
-      );
-      sqlite3_free(errmsg);
-   }
-
-   return rc == SQLITE_OK;
-}
-
-bool ProjectFileIO::TransactionRollback(const wxString &name)
-{
-   char *errmsg = nullptr;
-
-   int rc = sqlite3_exec(DB(),
-                         wxT("ROLLBACK TO ") + name + wxT(";"),
-                         nullptr,
-                         nullptr,
-                         &errmsg);
-
-   if (errmsg)
-   {
-      SetDBError(
-         XO("Failed to release savepoint:\n\n%s").Format(name)
-      );
-      sqlite3_free(errmsg);
-   }
-
-   return rc == SQLITE_OK;
-}
-
 static int ExecCallback(void *data, int cols, char **vals, char **names)
 {
    auto &cb = *static_cast<const ProjectFileIO::ExecCB *>(data);
@@ -498,9 +444,9 @@ int ProjectFileIO::Exec(const char *query, const ExecCB &callback)
    if (rc != SQLITE_ABORT && errmsg)
    {
       SetDBError(
-         XO("Failed to execute a project file command:\n\n%s").Format(query)
+         XO("Failed to execute a project file command:\n\n%s").Format(query),
+         Verbatim(errmsg)
       );
-      mLibraryError = Verbatim(errmsg);
    }
    if (errmsg)
    {
@@ -1760,9 +1706,8 @@ bool ProjectFileIO::ImportProject(const FilePath &fileName)
    if (!xmlFile.ParseString(this, output.GetString()))
    {
       SetError(
-         XO("Unable to parse project information.")
+         XO("Unable to parse project information."), xmlFile.GetErrorStr()
       );
-      mLibraryError = xmlFile.GetErrorStr();
 
       return false;
    }
@@ -1837,9 +1782,9 @@ bool ProjectFileIO::LoadProject(const FilePath &fileName)
       if (!success)
       {
          SetError(
-            XO("Unable to parse project information.")
+            XO("Unable to parse project information."),
+            xmlFile.GetErrorStr()
          );
-         mLibraryError = xmlFile.GetErrorStr();
          return false;
       }
 
@@ -2113,37 +2058,30 @@ wxLongLong ProjectFileIO::GetFreeDiskSpace() const
    return -1;
 }
 
-const TranslatableString &ProjectFileIO::GetLastError() const
-{
-   return mLastError;
-}
-
-const TranslatableString &ProjectFileIO::GetLibraryError() const
-{
-   return mLibraryError;
-}
-
-void ProjectFileIO::SetError(const TranslatableString &msg)
-{
-   mLastError = msg;
-   mLibraryError = {};
-}
-
-void ProjectFileIO::SetDBError(const TranslatableString &msg)
+const TranslatableString &ProjectFileIO::GetLastError()
 {
    auto &currConn = CurrConn();
-   mLastError = msg;
-   wxLogDebug(wxT("SQLite error: %s"), mLastError.Debug());
-   printf("   Lib error: %s", mLastError.Debug().mb_str().data());
+   return currConn->GetLastError();
+}
 
-   if (currConn)
-   {
-      mLibraryError = Verbatim(sqlite3_errmsg(currConn->DB()));
-      wxLogDebug(wxT("   Lib error: %s"), mLibraryError.Debug());
-      printf("   Lib error: %s", mLibraryError.Debug().mb_str().data());
-   }
+const TranslatableString &ProjectFileIO::GetLibraryError()
+{
+   auto &currConn = CurrConn();
+   return currConn->GetLibraryError();
+}
 
-   wxASSERT(false);
+void ProjectFileIO::SetError(
+   const TranslatableString &msg, const TranslatableString &libraryError )
+{
+   auto &currConn = CurrConn();
+   currConn->SetError(msg, libraryError);
+}
+
+void ProjectFileIO::SetDBError(
+   const TranslatableString &msg, const TranslatableString &libraryError)
+{
+   auto &currConn = CurrConn();
+   currConn->SetDBError(msg, libraryError);
 }
 
 void ProjectFileIO::SetBypass()
@@ -2447,41 +2385,3 @@ int ProjectFileIO::get_varint(const unsigned char *ptr, int64_t *out)
 
    return 9;
 }
-
-TransactionScope::TransactionScope(ProjectFileIO &projectFileIO,
-                                             const char *name)
-:  mIO(projectFileIO),
-   mName(name)
-{
-   mInTrans = mIO.TransactionStart(mName);
-   if ( !mInTrans )
-      // To do, improve the message
-      throw SimpleMessageBoxException( XO("Database error") );
-}
-
-TransactionScope::~TransactionScope()
-{
-   if (mInTrans)
-   {
-      // Rollback AND REMOVE the transaction
-      // -- must do both; rolling back a savepoint only rewinds it
-      // without removing it, unlike the ROLLBACK command
-      if (!(mIO.TransactionRollback(mName) &&
-            mIO.TransactionCommit(mName) ) )
-      {
-         // Do not throw from a destructor!
-         // This has to be a no-fail cleanup that does the best that it can.
-      }
-   }
-}
-
-bool TransactionScope::Commit()
-{
-   if ( !mInTrans )
-      // Misuse of this class
-      THROW_INCONSISTENCY_EXCEPTION;
-
-   mInTrans = !mIO.TransactionCommit(mName);
-
-   return mInTrans;
-}
diff --git a/src/ProjectFileIO.h b/src/ProjectFileIO.h
index 4434cb70f..ee95cfae2 100644
--- a/src/ProjectFileIO.h
+++ b/src/ProjectFileIO.h
@@ -24,7 +24,6 @@ struct sqlite3_stmt;
 struct sqlite3_value;
 
 class AudacityProject;
-class TransactionScope;
 class DBConnection;
 class ProjectSerializer;
 class SqliteSampleBlock;
@@ -104,8 +103,8 @@ public:
    // specific database. This is the workhorse for the above 3 methods.
    static int64_t GetDiskUsage(DBConnection *conn, SampleBlockID blockid);
 
-   const TranslatableString &GetLastError() const;
-   const TranslatableString &GetLibraryError() const;
+   const TranslatableString &GetLastError();
+   const TranslatableString &GetLibraryError();
 
    // Provides a means to bypass "DELETE"s at shutdown if the database
    // is just going to be deleted anyway.  This prevents a noticable
@@ -130,10 +129,6 @@ public:
    // The last compact check found unused blocks in the project file
    bool HadUnused();
 
-   bool TransactionStart(const wxString &name);
-   bool TransactionCommit(const wxString &name);
-   bool TransactionRollback(const wxString &name);
-
    // In one SQL command, delete sample blocks with ids in the given set, or
    // (when complement is true), with ids not in the given set.
    bool DeleteBlocks(const BlockIDs &blockids, bool complement);
@@ -142,6 +137,8 @@ public:
    // 0 for success or non-zero to stop the query
    using ExecCB = std::function<int(int cols, char **vals, char **names)>;
 
+   DBConnection &GetConnection();
+
 private:
    void WriteXMLHeader(XMLWriter &xmlFile) const;
    void WriteXML(XMLWriter &xmlFile, bool recording = false, const std::shared_ptr<TrackList> &tracks = nullptr) /* not override */;
@@ -197,8 +194,13 @@ private:
                bool prune = false,
                const std::shared_ptr<TrackList> &tracks = nullptr);
 
-   void SetError(const TranslatableString & msg);
-   void SetDBError(const TranslatableString & msg);
+   //! Just set stored errors
+   void SetError(const TranslatableString & msg,
+      const TranslatableString &libraryError = {});
+
+   //! Set stored errors and write to log; and default libraryError to what database library reports
+   void SetDBError(const TranslatableString & msg,
+      const TranslatableString &libraryError = {});
 
    bool ShouldCompact(const std::shared_ptr<TrackList> &tracks);
 
@@ -234,27 +236,6 @@ private:
    Connection mPrevConn;
    FilePath mPrevFileName;
    bool mPrevTemporary;
-
-   TranslatableString mLastError;
-   TranslatableString mLibraryError;
-};
-
-// Make a savepoint (a transaction, possibly nested) with the given name;
-// roll it back at destruction time, unless an explicit Commit() happened first.
-// Commit() must not be called again after one successful call.
-// An exception is thrown from the constructor if the transaction cannot open.
-class TransactionScope
-{
-public:
-   TransactionScope(ProjectFileIO &projectFileIO, const char *name);
-   ~TransactionScope();
-
-   bool Commit();
-
-private:
-   ProjectFileIO &mIO;
-   bool mInTrans;
-   wxString mName;
 };
 
 class wxTopLevelWindow;
diff --git a/src/ProjectManager.cpp b/src/ProjectManager.cpp
index 835dbfe1e..e30c5fae5 100644
--- a/src/ProjectManager.cpp
+++ b/src/ProjectManager.cpp
@@ -15,6 +15,7 @@ Paul Licameli split from AudacityProject.cpp
 #include "AdornedRulerPanel.h"
 #include "AudioIO.h"
 #include "Clipboard.h"
+#include "DBConnection.h"
 #include "FileNames.h"
 #include "Menus.h"
 #include "ModuleManager.h"
@@ -740,7 +741,7 @@ void ProjectManager::OnCloseWindow(wxCloseEvent & event)
    projectFileIO.SetBypass();
 
    {
-      TransactionScope trans(projectFileIO, "Shutdown");
+      TransactionScope trans(projectFileIO.GetConnection(), "Shutdown");
 
       // This can reduce reference counts of sample blocks in the project's
       // tracks.
diff --git a/src/effects/Effect.cpp b/src/effects/Effect.cpp
index 0c8389a5d..ada488b92 100644
--- a/src/effects/Effect.cpp
+++ b/src/effects/Effect.cpp
@@ -27,6 +27,7 @@
 #include <wx/tokenzr.h>
 
 #include "../AudioIO.h"
+#include "../DBConnection.h"
 #include "../LabelTrack.h"
 #include "../Mix.h"
 #include "../PluginManager.h"
@@ -1215,7 +1216,7 @@ bool Effect::DoEffect(double projectRate,
    // This is for performance purposes only, no additional recovery implied
    auto &pProject = *const_cast<AudacityProject*>(FindProject()); // how to remove this const_cast?
    auto &pIO = ProjectFileIO::Get(pProject);
-   TransactionScope trans(pIO, "Effect");
+   TransactionScope trans(pIO.GetConnection(), "Effect");
 
    // Update track/group counts
    CountWaveTracks();