Hello @benoitduQC
I hope you are doing well, and thanks for reaching out.
Acrobat XI Pro is a discontinued version (support ended in October 2017), so no new language packs are available now, and the activation servers are also discontinued. Your interface switches back to English after registration because your license is for the North America (English-only) build. That license does not support switching the UI to French, even if you selected French during installation.
You may try the following workaround, but it may or may not work:
Modify Language Settings via Control Panel:
Go to Control Panel > Programs and Features.
Select Adobe Acrobat XI Pro from the list.
Click Change, then choose Modify.
Select Languages.
From the dropdown, choose French and set it to “This feature will be installed on the local hard drive.”
Click Install to apply the changes.
Switch Language at Launch:
After installation:
Hold the Ctrl key and launch Acrobat.
A pop-up will appear, allowing you to select the language from the installed options.
Choose French, and Acrobat may open in that language. See this article for more information: https://adobe.ly/4fPNzT3
Adobe strongly recommends that you update to the latest versions of Adobe Acrobat and Adobe Acrobat Reader. By updating installations to the latest versions, you benefit from the latest functional enhancements and improved security measures.
I hope this helps.
Thanks,
Anand Sri | Acrobat Community Team.
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