Introduction
The convenience of auto-translation missing in Subtitle Edit can be quickly overshadowed when the process skips entire blocks or leaves blank lines in the output file. This frustrating issue means your translated script is incomplete, requiring manual review of thousands of lines to find the missing text.
The primary cause of these missing lines in subtitle edit is almost always a temporary communication failure with the external translation API (Google, Gemini, DeepL).
However, local issues such as outdated software versions or batch-processing settings can also interrupt the data flow. By isolating the problem and using targeted batch tools, you can ensure a complete and successful translation.
What Causes Subtitle Edit to Skip Lines During Translation?
Missing lines in subtitle edit are symptomatic of an error that occurs between Subtitle Edit requesting the translation and the external service delivering the result.
The most frequent culprit is API Block Size Limits or Timeouts. Translation services often limit the number of characters or lines they will process in a single block request to prevent abuse. If the API hits this limit or experiences a temporary server lag, it may return a partial result, leaving subsequent lines untranslated and blank.
Another significant issue is a Software Bug in Older Versions. Early or unstable releases of Subtitle Edit can contain bugs that cause the translation routine to misalign the source and target lines, especially in complex batch processes, resulting in untranslated sections (Source 1.1).
Finally, Internal Formatting Corruption can confuse the parser. Although the time codes remain, the presence of specific malformed tags or very short, empty lines in the source file can disrupt the API’s structured output, causing the line to be skipped.
How to Check and Update Subtitle Edit to Fix Skips
Before troubleshooting the API connection, ensure you are running the most stable and current version of the software, as many skip errors are fixed in patches.
Developers constantly push updates to improve API compatibility and fix bugs that cause translation blocks or alignment errors (Source 1.1). Using outdated software is the most common reason for persistent translation issues.
Verifying Your Software Version
Open Subtitle Edit and go to Help > Check for updates.
Install any available stable update immediately. If you are using an older version (e.g., 4.0.3), upgrading to the latest release often resolves known communication bugs that lead to blocks of untranslated text.
Trying Beta/Fixed Versions
If the problem is very recent and persists even after a general update, search the official Subtitle Edit forums or GitHub page for a specific Beta version that addresses recent API issues (Source 1.1). Developers sometimes release quick fixes for translation bugs that haven’t made it into the main release.
How to Re-Translate Missing Lines Efficiently
Once the translation has failed, you do not need to restart the entire process; you can target only the blank lines for a rapid fix.
Re-translating the entire file is time-consuming and unnecessary. Using Subtitle Edit’s selection tools, you can isolate the blank lines and instruct the software to process only those specific blocks.
Isolating Untranslated (Blank) Lines
First, delete all the existing blank lines that result from the failed attempt. Select all lines ( Ctrl+A), right-click, and choose “Remove blank lines.”
Now, scroll through the list to identify the missing translated lines. Manually select all the source lines that were skipped by the initial translation (use Ctrl + clickto select non-contiguous lines).
Auto-Translating Selected Lines Only
Right-click the selection and choose “Auto-translate selected lines.”
The software will send a much smaller, targeted request to the API, which is less likely to hit a block limit or timeout, ensuring a complete translation for the missing text.
How to Fix Skips by Using Individual Line Translation
If the default batch translation mode consistently skips lines, you can override the block processing and force the API to handle each line separately.
The default translation mode sends large chunks of text to the API at once for speed, but this increases the risk of the entire block failing. Switching to individual line mode is slower but significantly more reliable.
Changing the Translation Mode
Go to Options > Settings > Translation .
Look for a setting that controls the translation method (e.g., “Translate each line individually” or an option that controls the “block size”).
Select the individual line option. Although the entire translation process will take longer, the risk of a complete block failure is almost eliminated because the software makes small, separate requests.
Dealing with Increased Time
Be prepared for a slower process. While a 40-minute episode might translate in under a minute in batch mode, individual-line translation can take several minutes (Source 1.1). Run the translation and allow the process to finish without interruption.
How to Prevent Errors Caused by Source File Corruption
The translation engine may refuse to process specific lines if they contain unexpected formatting or structural problems in the source file.
Even if the source subtitle file displays correctly, it may contain specific characters, malformed tags, or very short lines that confuse the external API’s parser, causing it to skip the output line.
Running “Fix Common Errors” Preemptively
Before initiating the auto-translation, go to Tools > Fix common errors ( Ctrl+Shift+F).
Run a check to clean up structural issues. Ensure you choose:
- Remove empty lines (Source 4.1).
- Remove start/end tags in empty lines.
- Fix overlapping display times.
A structurally clean source file minimizes the likelihood that the translation engine misinterprets the line data and skips the translated text.
How to Troubleshoot API Connection Issues (Timeout/Block)
Persistent missing lines in subtitle edits often point to a connection or rate-limiting issue with the translation provider itself.
If the issue started suddenly, the API may have recently changed its block size limit, or your network’s firewall or VPN may be interfering with data exchange.
Switching Translation Engines
If one engine (e.g., Google) consistently skips lines, switch to a different available engine in Options > Settings > Translation (e.g., Gemini, DeepL, or Bing Translator). A different API may have different block limits or a more stable connection on your network (Source 1.1).
Checking API Keys
If you are using a paid service like DeepL, ensure your API key is correctly entered in the settings. An invalid or expired key will cause the translation to fail instantly or irregularly, leading to skipped lines.
Frequently Asked Questions About Missing Translation Lines
Why does the auto-translate feature sometimes leave a few blank lines?
This usually indicates a timeout or block limit was reached by the external translation API (Google/Gemini). The API processes the subtitle file in blocks; if one block fails, the corresponding lines are returned blank.
How do I force Subtitle Edit to translate the blank lines?
Manually delete the blank lines, then select only the source lines that were skipped (using Ctrl + click). Right-click the selection and choose “Auto-translate selected lines.” This sends a smaller, targeted request that is less likely to fail.
Does having long lines in the source file cause lines to be skipped?
Yes. If the total character count of a subtitle block sent to the API is too high, the request might be rejected, leading to skipped lines. You can try changing the translation mode to “Translate each line individually” to avoid this block-size problem.
Should I update Subtitle Edit to fix missing lines?
Yes, absolutely. Missing lines in subtitle edit and slow translation speed are often caused by outdated software versions that have communication bugs with the latest API endpoints (Source 1.1). Always ensure you are on the newest stable release.
Why does the translation work perfectly for the first half of the movie but skip lines in the second half?
This is a classic sign of an API timeout due to the size of the request. The initial connection works, but the full batch request takes too long to process, causing the server to cut off the data stream halfway through.
Is it faster to re-translate the whole file or fix the missing lines manually?
It is almost always faster to fix the missing lines in subtitle edit manually or use the “Auto-translate selected lines” feature. Re-translating the entire file (especially when using individual-line mode) is unnecessary and time-consuming.
Does switching the translation engine help with missing lines?
Yes. Switching to a different API (eg, from Google to Gemini) can help, as different providers have different server configurations and block size limits, which may lead to a more stable connection for your specific file.
Can clearing the Subtitle Edit cache fix the translation failure?
While not the primary fix, clearing the cache or deleting the Settings.xmlfile (by closing and restarting the program) can resolve deep-seated software bugs that interfere with network functions, which is a good final troubleshooting step.
