diff --git a/src/neptune_scale/__init__.py b/src/neptune_scale/__init__.py
index 2bc91f16..cc545bfe 100644
--- a/src/neptune_scale/__init__.py
+++ b/src/neptune_scale/__init__.py
@@ -59,6 +59,7 @@
 )
 from neptune_scale.envs import (
     API_TOKEN_ENV_NAME,
+    OPERATIONS_TIMEOUT_SECONDS,
     PROJECT_ENV_NAME,
 )
 from neptune_scale.exceptions import (
@@ -66,6 +67,7 @@
     NeptuneProjectNotProvided,
 )
 from neptune_scale.parameters import (
+    DEFAULT_OPERATIONS_TIMEOUT_SECONDS,
     MAX_EXPERIMENT_NAME_LENGTH,
     MAX_FAMILY_LENGTH,
     MAX_QUEUE_SIZE,
@@ -273,10 +275,8 @@ def __init__(
             self.wait_for_processing(verbose=False)
 
     def _handle_signal(self, signum: int, frame: Any) -> None:
-        if not self._is_closing:
-            signame = safe_signal_name(signum)
-            logger.debug(f"Received signal {signame}. Terminating.")
-
+        signame = safe_signal_name(signum)
+        logger.debug(f"Received signal {signame}")
         self.terminate()
 
     @property
@@ -294,21 +294,23 @@ def resources(self) -> tuple[Resource, ...]:
             self._errors_monitor,
         )
 
-    def _close(self, *, wait: bool = True) -> None:
+    def _close(self, *, wait: bool = True, timeout: Optional[float] = None) -> None:
+        logger.debug(f"Run is closing, wait={wait}, is_closing={self._is_closing}")
         with self._lock:
             if self._is_closing:
                 return
 
             self._is_closing = True
 
-            logger.debug(f"Run is closing, wait={wait}")
-
         if self._sync_process.is_alive():
             if wait:
-                self.wait_for_processing()
-
-            self._sync_process.terminate()
-            self._sync_process.join()
+                self.wait_for_processing(timeout=timeout)
+                self._sync_process.terminate()
+                self._sync_process.join()
+            else:
+                # If we don't care about waiting, it means we're trying to abort the run on error,
+                # so make it quick
+                self._sync_process.kill()
 
         if self._lag_tracker is not None:
             self._lag_tracker.interrupt()
@@ -351,14 +353,22 @@ def my_error_callback(exc):
         if self._exit_func is not None:
             atexit.unregister(self._exit_func)
             self._exit_func = None
+
+        # Force cleanup in _close() to make sure we're not waiting for any threads / processes
+        self._is_closing = False
         self._close(wait=False)
 
-    def close(self) -> None:
+    def close(self, timeout: Optional[float] = None) -> None:
         """
         Closes the connection to Neptune and waits for data synchronization to be completed.
 
         Use to finalize a regular run your model-training script.
 
+        Args:
+            timeout (float, optional): Maximum time in seconds to wait for the remaining operations to complete.
+                If the timeout is reached `TimeoutError` is raised. If not provided, the value
+                of `NEPTUNE_OPERATIONS_TIMEOUT_SECONDS`. If not set, the default value of 300sec is used.
+
         Example:
             ```
             from neptune_scale import Run
@@ -373,7 +383,7 @@ def close(self) -> None:
         if self._exit_func is not None:
             atexit.unregister(self._exit_func)
             self._exit_func = None
-        self._close(wait=True)
+        self._close(wait=True, timeout=timeout)
 
     def _create_run(
         self,
@@ -583,17 +593,22 @@ def _wait(
         timeout: Optional[float] = None,
         verbose: bool = True,
     ) -> None:
+        if timeout is None:
+            timeout = float(os.getenv(OPERATIONS_TIMEOUT_SECONDS, DEFAULT_OPERATIONS_TIMEOUT_SECONDS))
+
+        if timeout <= 0:
+            raise ValueError(f"Timeout must be greater than 0, but got {timeout}")
+
         if verbose:
             logger.info(f"Waiting for all operations to be {phrase}")
 
-        if timeout is None and verbose:
-            logger.warning("No timeout specified. Waiting indefinitely")
-
-        begin_time = time.time()
-        wait_time = min(sleep_time, timeout) if timeout is not None else sleep_time
+        timeout_left = timeout
         last_print_timestamp: Optional[float] = None
 
         while True:
+            t0 = time.monotonic()
+            wait_time = min(sleep_time, timeout_left)
+
             try:
                 with self._lock:
                     if not self._sync_process.is_alive():
@@ -611,6 +626,10 @@ def _wait(
                     wait_condition.wait(timeout=wait_time)
                     value = wait_value.value
 
+                timeout_left -= time.monotonic() - t0
+                if timeout_left <= 0:
+                    raise TimeoutError(f"Timeout of {timeout}s reached while waiting for all operations to be {phrase}")
+
                 last_queued_sequence_id = self._operations_queue.last_sequence_id
 
                 if value == -1:
@@ -636,7 +655,7 @@ def _wait(
                     )
                 else:
                     # Reaching the last queued sequence ID means that all operations were submitted
-                    if value >= last_queued_sequence_id or (timeout is not None and time.time() - begin_time > timeout):
+                    if value >= last_queued_sequence_id:
                         break
             except KeyboardInterrupt:
                 if verbose:
@@ -654,7 +673,9 @@ def wait_for_submission(self, timeout: Optional[float] = None, verbose: bool = T
         See wait_for_processing().
 
         Args:
-            timeout (float, optional): In seconds, the maximum time to wait for submission.
+            timeout (float, optional): Maximum time in seconds to wait for the remaining operations to complete.
+                If the timeout is reached `TimeoutError` is raised. If not provided, the value
+                of `NEPTUNE_OPERATIONS_TIMEOUT_SECONDS`. If not set, the default value of 300sec is used.
             verbose (bool): If True (default), prints messages about the waiting process.
         """
         self._wait(
@@ -673,7 +694,9 @@ def wait_for_processing(self, timeout: Optional[float] = None, verbose: bool = T
         Once the call is complete, the data is saved in Neptune.
 
         Args:
-            timeout (float, optional): In seconds, the maximum time to wait for processing.
+            timeout (float, optional): Maximum time in seconds to wait for the remaining operations to complete.
+                If the timeout is reached `TimeoutError` is raised. If not provided, the value
+                of `NEPTUNE_OPERATIONS_TIMEOUT_SECONDS`. If not set, the default value of 300sec is used.
             verbose (bool): If True (default), prints messages about the waiting process.
         """
         self._wait(
diff --git a/src/neptune_scale/envs.py b/src/neptune_scale/envs.py
index 02e0f9ff..f529e273 100644
--- a/src/neptune_scale/envs.py
+++ b/src/neptune_scale/envs.py
@@ -1,11 +1,12 @@
 PROJECT_ENV_NAME = "NEPTUNE_PROJECT"
-
 API_TOKEN_ENV_NAME = "NEPTUNE_API_TOKEN"
+ALLOW_SELF_SIGNED_CERTIFICATE = "NEPTUNE_ALLOW_SELF_SIGNED_CERTIFICATE"
 
 DISABLE_COLORS = "NEPTUNE_DISABLE_COLORS"
-
 DEBUG_MODE = "NEPTUNE_DEBUG_MODE"
 
 SUBPROCESS_KILL_TIMEOUT = "NEPTUNE_SUBPROCESS_KILL_TIMEOUT"
 
-ALLOW_SELF_SIGNED_CERTIFICATE = "NEPTUNE_ALLOW_SELF_SIGNED_CERTIFICATE"
+# Default timeout used to wait for operations to be processed by the Neptune backend.
+# Affects Run.wait*() and Run.close*() methods.
+OPERATIONS_TIMEOUT_SECONDS = "NEPTUNE_OPERATIONS_TIMEOUT_SECONDS"
diff --git a/src/neptune_scale/parameters.py b/src/neptune_scale/parameters.py
index b2e8bb62..c40e6af9 100644
--- a/src/neptune_scale/parameters.py
+++ b/src/neptune_scale/parameters.py
@@ -29,6 +29,7 @@
 MINIMAL_WAIT_FOR_ACK_SLEEP_TIME = 10
 STOP_MESSAGE_FREQUENCY = 5
 LAG_TRACKER_TIMEOUT = 1
+DEFAULT_OPERATIONS_TIMEOUT_SECONDS = 30 * 60
 
 # Status tracking
 MAX_REQUESTS_STATUS_BATCH_SIZE = 1000