- First, ensure that the issue isn't related to the download location. Make sure you have sufficient disk space in the directory where your downloads are being saved.

  - Start by disabling extensions in "Regular" mode. Extensions, especially download manager or privacy-focused extensions, can sometimes interfere with downloads.
    1. Go to `Menu > Add-ons` or `Menu > Extensions` (depending on your Firefox version).
    2. Disable all extensions.
    3. Restart Firefox and attempt a download in "Regular" mode.

  - Security software, including antivirus and firewall programs, can sometimes block or interfere with downloads. Make sure your security software is not causing the issue.

  - Incorrect proxy settings can also impact downloads. Ensure that your proxy settings are configured correctly.
    1. Go to `Menu > Options/Preferences > General`.
    2. Scroll down to the "Network Settings" section and click on "Settings."
    3. Ensure that the proxy settings are set to "No proxy" or the appropriate settings for your network.

  - There might be an issue with your download actions. You can reset these actions to the default settings.
    1. Type `about:preferences#general` in the Firefox address bar and press Enter.
    2. Scroll down to the "Files and Applications" section.
    3. Click on "Clear" next to "Download Actions."
    4. Restart Firefox and try downloading a file.

  - Malware on your computer can disrupt downloads. Run a malware scan using reputable antivirus software to ensure your system is clean.

  - If the issue persists, you can reset Firefox to its default settings. This will revert most settings to their factory defaults and may resolve the issue. Keep in mind that this will remove customizations.
    1. Type `about:support` in the Firefox address bar and press Enter.
    2. In the "Give Firefox a tune-up" section, click the "Refresh Firefox" button.

  - If none of the above steps resolve the issue, consider creating a new Firefox profile and testing downloads in "Regular" mode with the new profile. It helps determine if the problem is specific to your profile. You can do this by running the following command in the Windows Run dialog or Command Prompt:
    ```
    firefox.exe -P
    ```

hello Big962003, 1. **Check Download Location:** - First, ensure that the issue isn't related to the download location. Make sure you have sufficient disk space in the directory where your downloads are being saved. 2. **Disable Extensions:** - Start by disabling extensions in "Regular" mode. Extensions, especially download manager or privacy-focused extensions, can sometimes interfere with downloads. 1. Go to `Menu > Add-ons` or `Menu > Extensions` (depending on your Firefox version). 2. Disable all extensions. 3. Restart Firefox and attempt a download in "Regular" mode. 3. **Check Security Software:** - Security software, including antivirus and firewall programs, can sometimes block or interfere with downloads. Make sure your security software is not causing the issue. 4. **Check Proxy Settings:** - Incorrect proxy settings can also impact downloads. Ensure that your proxy settings are configured correctly. 1. Go to `Menu > Options/Preferences > General`. 2. Scroll down to the "Network Settings" section and click on "Settings." 3. Ensure that the proxy settings are set to "No proxy" or the appropriate settings for your network. 5. **Reset Download Actions:** - There might be an issue with your download actions. You can reset these actions to the default settings. 1. Type `about:preferences#general` in the Firefox address bar and press Enter. 2. Scroll down to the "Files and Applications" section. 3. Click on "Clear" next to "Download Actions." 4. Restart Firefox and try downloading a file. 6. **Check for Malware:** - Malware on your computer can disrupt downloads. Run a malware scan using reputable antivirus software to ensure your system is clean. 7. **Reset Firefox Settings:** - If the issue persists, you can reset Firefox to its default settings. This will revert most settings to their factory defaults and may resolve the issue. Keep in mind that this will remove customizations. 1. Type `about:support` in the Firefox address bar and press Enter. 2. In the "Give Firefox a tune-up" section, click the "Refresh Firefox" button. 8. **Profile Troubleshooting:** - If none of the above steps resolve the issue, consider creating a new Firefox profile and testing downloads in "Regular" mode with the new profile. It helps determine if the problem is specific to your profile. You can do this by running the following command in the Windows Run dialog or Command Prompt: ``` firefox.exe -P ``` Thanks regards

See this. https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_the-problem-does-not-happen-in-troubleshoot-mode