| Subject | English | Welsh |
| comp., MS | error bar | bar gwall (Usually used in statistical or scientific data, an error bar shows the potential error or degree of uncertainty relative to each data marker in a series) |
| comp., MS | error code | cod gwall (A return code that begins with E_ or DB_E_ and indicates that the method failed completely and was unable to do any useful work. Usually indicates a programming error) |
| comp., MS | error code | cod y gwall (One of four fields of an SCODE. It is a unique number that is assigned to represent the error or warning) |
| comp., MS | error log | log gwallau (A file that lists errors that were encountered during an operation) |
| comp., MS | error value | gwerth gwall (A value shown in Excel when there is an error in a formula, for example VALUE! or REF!) |
| comp., MS | sync error | gwall wrth gysoni (A problem that prevents sync from completing. Sync errors are typically caused by problems with the device, network folder, or other computer you are trying to sync with) |
| comp., MS | syntax error | gwall cystrawen (An error in the grammatical structure of the code or expression) |
| comp., MS | Windows Error Reporting | Cofnodi Gwallau Windows (The Windows technology that collects data on system crashes or hangs and sends it to Microsoft) |