[note] Solving fstatat canonical snap directory: Permission denied

📌 Introduction

When using Snap apps on Ubuntu, you might encounter a confusing permission error related to fstatat. This note documents a real-world issue, explores possible causes, and shares the simple solution that worked.

⭐ Note
This article was initially drafted with the help of ChatGPT based on a real issue I encountered. I verified the solution and revised the content to ensure accuracy and clarity for others facing similar problems.

📚 Prerequisite

• AppArmor
• LDAP (Lightweight Directory Access Protocol)
• fstatat
• snap

Below are some key concepts mentioned in this article:

Term	中文說明	English Description
AppArmor	Ubuntu 的一種安全模組，用來限制應用程式能存取的資源，例如檔案、網路。	A security module in Ubuntu that restricts what resources an application can access.
LDAP (Lightweight Directory Access Protocol)	一種常見的用戶驗證協定，常用於企業環境集中管理帳號。	A common user authentication protocol used for centralized account management, especially in enterprise environments.
fstatat	一個 Linux 系統呼叫，用來查詢檔案資訊。這個錯誤就是因為它失敗了。	A Linux system call used to get information about files. The error occurs when this call fails.
Snap	Ubuntu 推出的套件系統，讓應用程式更容易安裝、升級與隔離管理。	A packaging system by Ubuntu that makes applications easy to install, update, and sandbox.

• Non-standard home directory: The user’s home directory is located outside the default /home/username path, often on a different drive or mount point
• Home directory is symlinked: The home directory appears to be in /home/username, but it’s actually a symbolic link pointing to another location

🧭 Problem-solving Framework

Problem

cannot fstatat canonical snap directory: Permission denied

Root Cause Analysis

In general, there are two common causes for this issue:

1. The system is installed on an NTFS partition.
2. The home directory is symlinked to a non-standard location.

Check Filesystem Type

df -T /

Filesystem     Type 1K-blocks     Used Available Use% Mounted on
/dev/nvme0n1p4 ext4 669754920 44435324 591224492   7% /

The system is installed on an ext4 partition

Check for Symlinks

ls -l /home/hsiangjenli/Documents/github

drwxrwxr-x 10 hsiangjenli hsiangjenli 4096  一  27 17:05 blog
drwxrwxr-x 11 hsiangjenli hsiangjenli 4096  三  28 17:03 default-of-credit-card-clients-mlops
drwxrwxr-x  8 hsiangjenli hsiangjenli 4096  一  29 16:40 hsiangjenli.github.io
drwxrwxr-x  5 hsiangjenli hsiangjenli 4096  三  27 14:28 java-from-python
drwxrwxr-x  4 hsiangjenli hsiangjenli 4096  一  29 17:19 pic-bed
drwxrwxr-x 11 hsiangjenli hsiangjenli 4096  二  16 08:44 python-package-template
drwxrwxr-x  6 hsiangjenli hsiangjenli 4096  一  27 17:25 star-to-review

None of the folders are symbolic links

Why This Happens

I don’t know …

Solution

Surprisingly, running the following command solved the issue:

sudo dpkg-reconfigure apparmor

Enter the destination directory that you want to use

Reboot the computer~~

🔁 Recap

• ✅ The error cannot fstatat canonical snap directory: Permission denied is often related to AppArmor restrictions
• ✅ Common causes include:
  • Using an NTFS partition for your system or home directory
  • Having a symlinked or non-standard home directory
• 🔍 In this case:
  • The system is on an ext4 partition — ✅ not NTFS.
  • The home directory is not a symlink — ✅ not symlinked.
• ⚠️ The root cause remains unclear
• 🛠 The problem was resolved by:
  1. Running sudo dpkg-reconfigure apparmor
  2. Entering the actual path to the home directory during configuration
  3. Rebooting the system

🔗 References

• ‘Permission denied’ when running snap applications on Ubuntu 16.04 as a LDAP user
• Permission denied error when running apps installed as snap packages - Ubuntu 17.04