I am using Manager 17.9.50 Desktop version.
I am not able to do a Backup, but get the error as shown:
Thank you.
what is the location you are making the backup to? are you using the default file name for backup?
Dear @sharpdrivetek
Thank you for your reply.
I am not sure where to check on the location. I am not receiving the option to choose the backup location.
Do I check on the location on this screen:
when you click the 
button, it will ask for the location where to save the file.
can you explain how you are making the backup?
Dear sharpdrivetek
Thank you for your reply.
It gives me the error (first screen), when I am pressing the Backup button.
What else can I try to resolve this problem.
i am using the same version on desktop and i cannot reproduce the problem you are facing.
in your manager installation folder, there is a file ManagerServer.exe
run it, open your browser and go to 127.0.0.1:8080
it will ask for a password, just press enter and open your business file.
then try doing a backup. if the error repeats, atleast it may give more details about the error.
Dear sharpdrivetek
Thank you, I were able to do a backup by following your advice.
Unfortunally, when I tried to make a backup again, the same error message appear.
If I delete the company and import this file, will I be able to change the backup-destination or will the same error appear, since this is a backup?
@Meester, what is the exact name of the company you are backing up? I ask because in Manager you can name a company anything you want. But when you make a backup, you are relying upon the file-naming restrictions of your operating system. Manager, by default, adds a date in parentheses to the business name when making a backup. If your business name contains a character not allowed in file names by your operating system, you might get this error.
You can still have a name with “illegal” characters appear on your forms, because that name is taken from the Trading name field under Business Details in the Settings tab. So you could Rename your business to something with legal characters to solve the file-naming problem, and still keep the characters you want in the Trading name. If, for some reason, you don’t enter a trading name, Manager will use the business name instead.
Dear @Tut
Thank you for you reply.
The problem was that the filename contain a character that is not allowed.
I have use a red circle to indicate the character, see the following screen:
After removing the character the next window appear asking me the destination for backup.
Yes, that symbol is called a pipe ( | ). Windows does not allow that in file names.
If you still want a delimiter between those two parts of the name, try a hyphen ( - ) instead.