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CLS - Special Characters You Should Avoid Using and File Path, File Name, and Data Character Limitations

Views: 3456 Last Updated: 02/14/2023 09:37 am 100 Rating/ 1 Voters
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Number of Characters

Microsoft® Windows® file system is limited to 256 character or less for file path names; anything longer than 256 characters (including the file name) cannot be processed by the operating system and is therefore not accessible to On-Screen Takeoff.

Windows error that file path is too long

This is important to remember when downloading plans from various Planroom sites or moving images. The images or project files provided can be imbedded in multiple sub directories causing the plans to be unavailable to download, or in some cases causing your operating system to freeze.

Path names that exceed this maximum may also cause On-Screen Takeoff to display a red banner that reads Cannot Display Image.

If you receive a message, while downloading, stating that the destination path is too long or that the file cannot be download to the current location, contact the plan provider and inform them of this message.  If the error is received while you are moving images or databases to different locations, you will need to create shorter path names.

Special Note about Converting Image Files
Because the converters that On-Screen Takeoff uses basically create a command line entry to convert "This File" to "That File" the path name (including the file name and extension) needs to be less than 1/2 of the maximum (128 characters or less) or the conversion will fail.

Invalid/Reserved Characters

There are limitations on the characters you are allowed to use when creating the following:

  • Project Name - name that appears in the Cover Sheet (including Alternates and Changes Orders) 
  • Export Name - any file name you manually create when exporting information
  • Image Name - the name of individual images used in a project
  • Folder Name - the name of the project folder containing images and/or databases
  • Program Folders - the path/directory to any of the folders specified under Tools > Options > Folders
  • Masters - especially those synched between On-Screen Takeoff and Quick Bid: Labor Cost Codes, Payroll Classes, Condition Types, Job Types, Job Statuses
  • Condition Names and Bid Area or Typical Area Names Condition Names or Notes, Bid Areas, Typical Areas, Bid (Cover Sheet) Notes, 
  • Other sync'ed data fields Condition Notes, Bid (Cover Sheet) Notes


The following characters are considered reserved, and should not be used in any of the above examples.




















Apostrophe (single quotation mark)

"At" symbol

Back slash (these will show in the path to your image file, database, or export location, that's fine)

Forward slash (these will show in the path to your image file, database, or export location, that's fine)





Question mark

Double quotation mark

Less than

Greater than

Percent (with the exception of Bid Name)

Vertical Bar (pipe)


The following characters are acceptable to use (including any combination of letters (A-Z) and numbers (0-9), of course):

















Accent circumflex (caret)

Brace left

Brace right

Bracket opening (do not use Brackets in Bid Areas or Typical Areas names)

Bracket closing (do not use Brackets in Bid Areas or Typical Areas names)


Dollar sign

Equal sign

Exclamation point


Number sign

Parenthesis opening

Parenthesis closing



Product documentation (user guides) describes functionality in the latest version of each major release and may not match the functionality in the version you are using. Please check the Product Information and Downloads pages by clicking one of the product buttons above.

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