diff --git a/src/lck-windows.c b/src/lck-windows.c
index 478c79df..c019a6d5 100644
--- a/src/lck-windows.c
+++ b/src/lck-windows.c
@@ -226,12 +226,19 @@ static int suspend_and_append(mdbx_handle_array_t **array,
     (*array)->limit = limit * 2;
   }
 
-  HANDLE hThread = OpenThread(THREAD_SUSPEND_RESUME, FALSE, ThreadId);
+  HANDLE hThread = OpenThread(THREAD_SUSPEND_RESUME | THREAD_QUERY_INFORMATION,
+                              FALSE, ThreadId);
   if (hThread == NULL)
     return GetLastError();
+
   if (SuspendThread(hThread) == -1) {
+    int err = GetLastError();
+    DWORD ExitCode;
+    if (err == /* workaround for Win10 UCRT bug */ ERROR_ACCESS_DENIED ||
+        !GetExitCodeThread(hThread, &ExitCode) || ExitCode != STILL_ACTIVE)
+      err = MDBX_SUCCESS;
     CloseHandle(hThread);
-    return GetLastError();
+    return err;
   }
 
   (*array)->handles[(*array)->count++] = hThread;
@@ -316,9 +323,15 @@ int mdbx_suspend_threads_before_remap(MDBX_env *env,
 int mdbx_resume_threads_after_remap(mdbx_handle_array_t *array) {
   int rc = MDBX_SUCCESS;
   for (unsigned i = 0; i < array->count; ++i) {
-    if (ResumeThread(array->handles[i]) == -1)
-      rc = GetLastError();
-    CloseHandle(array->handles[i]);
+    const HANDLE hThread = array->handles[i];
+    if (ResumeThread(hThread) == -1) {
+      const int err = GetLastError();
+      DWORD ExitCode;
+      if (err != /* workaround for Win10 UCRT bug */ ERROR_ACCESS_DENIED &&
+          GetExitCodeThread(hThread, &ExitCode) && ExitCode == STILL_ACTIVE)
+        rc = err;
+    }
+    CloseHandle(hThread);
   }
   return rc;
 }
diff --git a/src/mdbx.c b/src/mdbx.c
index 8abb0508..ca3774d5 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -2295,18 +2295,20 @@ bailout:
             VALGRIND_CREATE_BLOCK(env->me_map, env->me_mapsize, "mdbx");
     }
 #endif
-  } else if (rc != MDBX_RESULT_TRUE) {
-    mdbx_error("failed resize datafile/mapping: "
-               "present %" PRIuPTR " -> %" PRIuPTR ", "
-               "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
-               env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper, limit_bytes,
-               rc);
   } else {
-    mdbx_notice("unable resize datafile/mapping: "
-                "present %" PRIuPTR " -> %" PRIuPTR ", "
-                "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
-                env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper, limit_bytes,
-                rc);
+    if (rc != MDBX_RESULT_TRUE) {
+      mdbx_error("failed resize datafile/mapping: "
+                 "present %" PRIuPTR " -> %" PRIuPTR ", "
+                 "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
+                 env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper,
+                 limit_bytes, rc);
+    } else {
+      mdbx_notice("unable resize datafile/mapping: "
+                  "present %" PRIuPTR " -> %" PRIuPTR ", "
+                  "limit %" PRIuPTR " -> %" PRIuPTR ", errcode %d",
+                  env->me_dbgeo.now, size_bytes, env->me_dbgeo.upper,
+                  limit_bytes, rc);
+    }
     if (!env->me_dxb_mmap.address) {
       env->me_flags |= MDBX_FATAL_ERROR;
       if (env->me_txn)
@@ -3161,6 +3163,16 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
       rc = mdbx_rdt_lock(env);
       if (unlikely(MDBX_IS_ERROR(rc)))
         return rc;
+      if (unlikely(env->me_flags & MDBX_FATAL_ERROR)) {
+        mdbx_rdt_unlock(env);
+        return MDBX_PANIC;
+      }
+#if defined(_WIN32) || defined(_WIN64)
+      if (unlikely(!env->me_map)) {
+        mdbx_rdt_unlock(env);
+        return MDBX_EPERM;
+      }
+#endif /* Windows */
       rc = MDBX_SUCCESS;
 
       if (unlikely(env->me_live_reader != env->me_pid)) {
@@ -3259,6 +3271,16 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
     rc = mdbx_txn_lock(env, F_ISSET(flags, MDBX_TRYTXN));
     if (unlikely(rc))
       return rc;
+    if (unlikely(env->me_flags & MDBX_FATAL_ERROR)) {
+      mdbx_txn_unlock(env);
+      return MDBX_PANIC;
+    }
+#if defined(_WIN32) || defined(_WIN64)
+    if (unlikely(!env->me_map)) {
+      mdbx_txn_unlock(env);
+      return MDBX_EPERM;
+    }
+#endif /* Windows */
 
     mdbx_jitter4testing(false);
     MDBX_meta *meta = mdbx_meta_head(env);
@@ -3318,8 +3340,11 @@ static int mdbx_txn_renew0(MDBX_txn *txn, unsigned flags) {
         goto bailout;
       }
       rc = mdbx_mapresize(env, txn->mt_end_pgno, upper_pgno);
-      if (rc != MDBX_SUCCESS)
+      if (rc != MDBX_SUCCESS) {
+        if (rc == MDBX_RESULT_TRUE)
+          rc = MDBX_MAP_RESIZED;
         goto bailout;
+      }
     }
     txn->mt_owner = mdbx_thread_self();
     return MDBX_SUCCESS;
@@ -3367,6 +3392,7 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
   if (unlikely(!env || !ret))
     return MDBX_EINVAL;
 
+  *ret = NULL;
   if (unlikely(env->me_signature != MDBX_ME_SIGNATURE))
     return MDBX_EBADSIGN;
 
@@ -3376,8 +3402,12 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
   if (unlikely(env->me_flags & MDBX_FATAL_ERROR))
     return MDBX_PANIC;
 
+#if !defined(_WIN32) && !defined(_WIN64)
+  /* Don't check env->me_map until lock to avoid race with re-mapping for
+   * shrinking */
   if (unlikely(!env->me_map))
     return MDBX_EPERM;
+#endif /* Windows */
 
   flags &= MDBX_TXN_BEGIN_FLAGS;
   flags |= env->me_flags & MDBX_WRITEMAP;
@@ -3388,16 +3418,21 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
 
   if (parent) {
     if (unlikely(parent->mt_signature != MDBX_MT_SIGNATURE))
-      return MDBX_EINVAL;
+      return MDBX_EBADSIGN;
 
     if (unlikely(parent->mt_owner != mdbx_thread_self()))
       return MDBX_THREAD_MISMATCH;
 
+#if defined(_WIN32) || defined(_WIN64)
+    if (unlikely(!env->me_map))
+      return MDBX_EPERM;
+#endif /* Windows */
+
     /* Nested transactions: Max 1 child, write txns only, no writemap */
     flags |= parent->mt_flags;
-    if (unlikely(flags & (MDBX_RDONLY | MDBX_WRITEMAP | MDBX_TXN_BLOCKED))) {
+    if (unlikely(flags & (MDBX_RDONLY | MDBX_WRITEMAP | MDBX_TXN_BLOCKED)))
       return (parent->mt_flags & MDBX_TXN_RDONLY) ? MDBX_EINVAL : MDBX_BAD_TXN;
-    }
+
     /* Child txns save MDBX_pgstate and use own copy of cursors */
     size = env->me_maxdbs * (sizeof(MDBX_db) + sizeof(MDBX_cursor *) + 1);
     size += tsize = sizeof(MDBX_ntxn);
@@ -3475,10 +3510,11 @@ int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags,
     rc = mdbx_txn_renew0(txn, flags);
   }
 
-  if (unlikely(rc)) {
+  if (unlikely(rc != MDBX_SUCCESS)) {
     if (txn != env->me_txn0)
       mdbx_free(txn);
   } else {
+    mdbx_assert(env, (txn->mt_flags & ~MDBX_RDONLY) == 0);
     txn->mt_signature = MDBX_MT_SIGNATURE;
     *ret = txn;
     mdbx_debug("begin txn %" PRIaTXN "%c %p on env %p, root page %" PRIaPGNO
@@ -4859,8 +4895,10 @@ int mdbx_txn_commit(MDBX_txn *txn) {
     rc = mdbx_sync_locked(
         env, env->me_flags | txn->mt_flags | MDBX_SHRINK_ALLOWED, &meta);
   }
-  if (unlikely(rc != MDBX_SUCCESS))
+  if (unlikely(rc != MDBX_SUCCESS)) {
+    env->me_flags |= MDBX_FATAL_ERROR;
     goto fail;
+  }
 
   if (likely(env->me_lck))
     env->me_lck->mti_readers_refresh_flag = false;
diff --git a/src/osal.c b/src/osal.c
index ee5b1f3f..c5dd5c03 100644
--- a/src/osal.c
+++ b/src/osal.c
@@ -1071,11 +1071,11 @@ int mdbx_mresize(int flags, mdbx_mmap_t *map, size_t size, size_t limit) {
                                    &ReservedSize, MEM_RESERVE, PAGE_NOACCESS);
   if (!NT_SUCCESS(status)) {
     ReservedAddress = NULL;
-    if (status != /* STATUS_CONFLICTING_ADDRESSES */ 0xC0000018 ||
-        limit == map->length)
+    if (status != /* STATUS_CONFLICTING_ADDRESSES */ 0xC0000018)
       goto bailout_ntstatus /* no way to recovery */;
 
-    /* assume we can change base address if mapping size changed */
+    /* assume we can change base address if mapping size changed or prev address
+     * couldn't be used */
     map->address = NULL;
   }
 
@@ -1132,8 +1132,8 @@ retry_mapview:;
 
   if (!NT_SUCCESS(status)) {
     if (status == /* STATUS_CONFLICTING_ADDRESSES */ 0xC0000018 &&
-        map->address && limit != map->length) {
-      /* try remap at another base address, but only if the limit is changing */
+        map->address) {
+      /* try remap at another base address */
       map->address = NULL;
       goto retry_mapview;
     }