Short answer
Convert one test file, save the proven settings as a profile, then attach that profile to separate input and output folders. Keep Just Converter open while the rule is working.
This guide covers Just Converter. Check requirements and download options before you begin.
On this page
When to use this method
Watch folders suit repeated arrivals with the same known settings. They are not a background Windows service and do not run while the desktop app is closed.
What you need before creating a watch folder
- One copied test file that represents the files you expect later.
- A saved profile that already produced a result you checked.
- Two separate folders, such as
Pictures\Convert incomingandPictures\Converted. Neither should be inside the other.
Create a predictable watch rule
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Test the settings
Run the exact conversion manually. Open the result and check it.
You should see: one completed file that is suitable for the real job.
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Save the profile
Choose Save custom profile and give the tested conversion settings a recognizable name. This is the profile the watch rule will use.
You should see: the new profile in the profile list.
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Create a rule with separate folders
Open Watch folders and choose New rule. Enter a Rule name, select the incoming Source folder and your tested Conversion profile, then choose a separate Output folder outside the source folder.
You should see: two different folder paths in the rule.
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Filter eligible files
Under Extension filters, set Include extensions to the types your profile supports, for example png,jpg. Use Exclude extensions if needed. Decide whether Include subfolders should be on. These filters match file extensions, not words in filenames; a profile's Naming pattern controls output names.
You should see: only the intended file types in the rule summary.
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Save, enable and check the rule
Turn on Rule enabled and choose Save watch rule. Keep Just Converter open, then copy one disposable supported file into the Source folder. Check Watch activity, then open the rule's Output folder in File Explorer and inspect the created file.
You should see: one completed conversion in the intended output folder. On a later launch, also check eligible files that arrived while the app was closed.
Watch folder behaviorWhen rules run, how missed files are handled and what can disable a rule.
- How it works
- New eligible files are processed while the app is running. After a restart, it can check for eligible files that arrived while it was closed. This check is called restart reconciliation.
- Important limit
- The app rejects overlapping source and output folders. Deleting the profile used by a rule disables that rule until you choose a valid profile again.
Checkpoint: prove the rule with one disposable file
Place one supported test file in the watched folder after its copy has finished. Confirm that exactly one expected output appears, the source remains available and the output does not return to the watched input tree. Only then allow the rule to process a larger folder.
If an expected file is not converted
Confirm that the app is open, the rule is enabled, the file matches the rule and the saved profile still passes the app's compatibility check, called preflight. Also check folder permissions and the per-file result. The app skips files that fail the rule, preflight, stability or permission checks.
The app checks size and modification time three times, two seconds apart, then confirms that no other program has the file locked. A file that is still copying or locked stays out of the job until it becomes stable.
Watch-rule problems
- Using overlapping input and output folders
- Using a synced or network file that never becomes stable
- Assuming the rule runs after the app closes
Automation checks
- The profile still exists and produces a valid file.
- Only intended formats enter the rule.
- Results do not return to the watched source tree.