diff --git a/lib/error/browserMissingSchema.js b/lib/error/browserMissingSchema.js
index 3f271499d4d..608cfd983e4 100644
--- a/lib/error/browserMissingSchema.js
+++ b/lib/error/browserMissingSchema.js
@@ -4,7 +4,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 
 class MissingSchemaError extends MongooseError {
diff --git a/lib/error/divergentArray.js b/lib/error/divergentArray.js
index 6bb527d0205..f266dbde449 100644
--- a/lib/error/divergentArray.js
+++ b/lib/error/divergentArray.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 class DivergentArrayError extends MongooseError {
   /**
diff --git a/lib/error/eachAsyncMultiError.js b/lib/error/eachAsyncMultiError.js
index 9c04020312b..b14156a09a3 100644
--- a/lib/error/eachAsyncMultiError.js
+++ b/lib/error/eachAsyncMultiError.js
@@ -4,7 +4,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 
 /**
diff --git a/lib/error/invalidSchemaOption.js b/lib/error/invalidSchemaOption.js
index 2ab1aa9497e..089dc6a03ef 100644
--- a/lib/error/invalidSchemaOption.js
+++ b/lib/error/invalidSchemaOption.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 class InvalidSchemaOptionError extends MongooseError {
   /**
diff --git a/lib/error/missingSchema.js b/lib/error/missingSchema.js
index 50c81054a90..2b3bf242526 100644
--- a/lib/error/missingSchema.js
+++ b/lib/error/missingSchema.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 class MissingSchemaError extends MongooseError {
   /**
diff --git a/lib/error/notFound.js b/lib/error/notFound.js
index e1064bb89d9..19a22f3a101 100644
--- a/lib/error/notFound.js
+++ b/lib/error/notFound.js
@@ -4,7 +4,7 @@
  * Module dependencies.
  */
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 const util = require('util');
 
 class DocumentNotFoundError extends MongooseError {
diff --git a/lib/error/objectExpected.js b/lib/error/objectExpected.js
index 6506f60656a..9f7a8116618 100644
--- a/lib/error/objectExpected.js
+++ b/lib/error/objectExpected.js
@@ -4,7 +4,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 
 class ObjectExpectedError extends MongooseError {
diff --git a/lib/error/objectParameter.js b/lib/error/objectParameter.js
index 295582e2484..b3f5b80849d 100644
--- a/lib/error/objectParameter.js
+++ b/lib/error/objectParameter.js
@@ -4,7 +4,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 class ObjectParameterError extends MongooseError {
   /**
diff --git a/lib/error/overwriteModel.js b/lib/error/overwriteModel.js
index 1ff180b0498..8904e4e74b3 100644
--- a/lib/error/overwriteModel.js
+++ b/lib/error/overwriteModel.js
@@ -5,7 +5,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 
 class OverwriteModelError extends MongooseError {
diff --git a/lib/error/parallelSave.js b/lib/error/parallelSave.js
index e0628576de7..57ac458238d 100644
--- a/lib/error/parallelSave.js
+++ b/lib/error/parallelSave.js
@@ -4,7 +4,7 @@
  * Module dependencies.
  */
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 class ParallelSaveError extends MongooseError {
   /**
diff --git a/lib/error/strict.js b/lib/error/strict.js
index 393ca6e1fc7..6cf4cf91141 100644
--- a/lib/error/strict.js
+++ b/lib/error/strict.js
@@ -4,7 +4,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 
 class StrictModeError extends MongooseError {
diff --git a/lib/error/strictPopulate.js b/lib/error/strictPopulate.js
index f7addfa5287..288799897bc 100644
--- a/lib/error/strictPopulate.js
+++ b/lib/error/strictPopulate.js
@@ -4,7 +4,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 class StrictPopulateError extends MongooseError {
   /**
diff --git a/lib/error/validator.js b/lib/error/validator.js
index 4ca7316d7bf..f7ee2ef4761 100644
--- a/lib/error/validator.js
+++ b/lib/error/validator.js
@@ -4,7 +4,7 @@
 
 'use strict';
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 
 class ValidatorError extends MongooseError {
diff --git a/lib/error/version.js b/lib/error/version.js
index b357fb16ca3..85f2921a517 100644
--- a/lib/error/version.js
+++ b/lib/error/version.js
@@ -4,7 +4,7 @@
  * Module dependencies.
  */
 
-const MongooseError = require('./');
+const MongooseError = require('./mongooseError');
 
 class VersionError extends MongooseError {
   /**
diff --git a/lib/index.js b/lib/index.js
index 6247d6a4d5c..67534e9e793 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -4,10 +4,14 @@
  * Module dependencies.
  */
 
-require('./driver').set(require('./drivers/node-mongodb-native'));
+const mongodbDriver = require('./drivers/node-mongodb-native');
+
+require('./driver').set(mongodbDriver);
 
 const mongoose = require('./mongoose');
 
+mongoose.setDriver(mongodbDriver);
+
 mongoose.Mongoose.prototype.mongo = require('mongodb');
 
 module.exports = mongoose;
diff --git a/lib/mongoose.js b/lib/mongoose.js
index 915720b59f7..49392bfd70f 100644
--- a/lib/mongoose.js
+++ b/lib/mongoose.js
@@ -68,8 +68,8 @@ function Mongoose(options) {
     autoCreate: true,
     autoSearchIndex: false
   }, options);
-  const createInitialConnection = utils.getOption('createInitialConnection', this.options);
-  if (createInitialConnection == null || createInitialConnection) {
+  const createInitialConnection = utils.getOption('createInitialConnection', this.options) ?? true;
+  if (createInitialConnection && this.__driver != null) {
     const conn = this.createConnection(); // default connection
     conn.models = this.models;
   }
@@ -169,6 +169,9 @@ Mongoose.prototype.setDriver = function setDriver(driver) {
   const oldDefaultConnection = _mongoose.connections[0];
   _mongoose.connections = [new Connection(_mongoose)];
   _mongoose.connections[0].models = _mongoose.models;
+  if (oldDefaultConnection == null) {
+    return _mongoose;
+  }
 
   // Update all models that pointed to the old default connection to
   // the new default connection, including collections