Sorry for posting 2 messages in 1 hour.
Just after posting the previous message, I did an action that resulted in a 500 error.
In the page manager, I duplicated an existing page in
(and sorry for this one more, I did a bad manipulation and I haven’t find to edit a message, I can only edit the title)
Just after posting the previous message, I did an action that resulted in a 500 error.
In the page manager, I duplicated an existing page in a new folder. Going back to my text editor, I first realized that an other page, in an other folder had been deleted. Fortunately, I was able to recover it as the text editor tab was open 
So I re-did the same operation with another file, and then SC thrown a 500 error. Looking at the log I discovered that the error was caused because of a missing file (that wasn’t opened this time). So I went to the back-up, tried to copy paste the one missing and it came back.
Here is the log :
[2018-09-06 00:10:29] app.ERROR: Sitecake\Resources\Exception\ResourceNotFoundException (500): Source file resource "(index.html, index.htm, index.php, index.shtml, index.php5)" not found in [...\sitecake\2.4.8\src\Sitecake\PageManager\SourceFileHandler.php, line 105] Stack Trace: #0 ...\sitecake\2.4.8\src\Sitecake\PageManager\SourceFileHandler.php(189): Sitecake\PageManager\SourceFileHandler->getDefaultPage('projects') #1 ...\sitecake\2.4.8\src\Sitecake\PageManager\SourceFileHandler.php(68): Sitecake\PageManager\SourceFileHandler->normalizePath('projects') #2 ...\sitecake\2.4.8\src\Sitecake\Resources\ResourceManager.php(259): Sitecake\PageManager\SourceFileHandler->supports('projects') #3 ...\sitecake\2.4.8\src\Sitecake\Resources\ResourceManager.php(1036): Sitecake\Resources\ResourceManager->getSupportingHandler('projects') #4 ...\sitecake\2.4.8\src\Sitecake\Content\PageRenderAwareTrait.php(182): Sitecake\Resources\ResourceManager->urlToPath('/projects/') #5
I am afraid that it happened again, what should I do for it doesn’t?
Thanks for sharing. I’ll look into it.