In the separation agreement of 1968 the plaintiff agreed to make a “valid effort” to claim as a deduction the $31,000.00 which was paid to her by defendant for her counsel fees in the calendar year of 1968. Plaintiff did claim this deduction in both her federal and state income tax returns.
In his letter of 4 November 1975 the Chief Counsel of Internal Revenue Service, proposing settlement of the action by this defendant against the United States based on the claimed deduction for counsel fees, wrote: “To avoid a whipsaw and protect the revenue, the District Director took inconsistent positions in disallowing the claimed alimony deductions to Fred Stanback and in taxing to Vanita Stanback all of Fred’s payments to her.”
The Chief Counsel added, “[Y]ou propose to settle the alimony issue out of court by conceding that the amount of $31,000.00 attributable to attorney’s fees, is not alimony . . . . [T]he pending offer had been accepted on behalf of the Attor-nel General. Upon being advised of such settlement, the District Office would solicit a refund claim from Vanita and, when filed, would proceed to adjust the return and have the overpayment processed and refund check issued. The period within which the claim may be filed expires February 12, 1976.”
It, thus, appears clear that if the plaintiff would file a refund claim based on the deduction of $31,000.00 for counsel fees in the year of 1968, the claim would be honored and a refund check issued. The plaintiff, in her settlement agreement of 1968 with defendant, contracted to make a “valid” effort to claim this deduction. In the sense used in the settlement agreement, we construe a “valid” effort to mean a “reasonable” *326effort, and that plaintiff agreed to pursue those remedies that a reasonable person would pursue in seeking a refund for an overpayment of taxes.
The plaintiff filed a claim based on the $31,000.00 counsel fee deduction, and also deductions of $10,000.00 for child support and $4,500.00 for an automobile in 1973. In his settlement letter of 4 November 1975, the Chief Counsel of Internal Revenue Service, referring to plaintiff’s 1973 claim, wrote: “But the claim for refund of the original tax, obviously, had been filed out of time.” The plaintiff disputes this statement of Chief Counsel, testifying that the District Director had advised her that the claim was filed in apt time. The plaintiff further contends that to now file a claim based only on the counsel fee deduction would prejudice her claim for refund based on additional deductions of $14,500.00 for child support and automobile.
We decline to rule on the validity of plaintiff’s 1973 claim, either on whether the claim was filed in apt time or whether she would be prejudiced in her 1973 claim by now filing a claim as proposed in the settlement letter of Chief Counsel. In view of admitted inconsistent rulings on the claims of plaintiff and defendant and the purported disagreement within the Internal Revenue Service as to whether plaintiff’s 1973 filing was made in apt time, we studiously avoid forecasting any final determination by the Internal Revenue Service. However, we must consider the evidence offered by both plaintiff and defendant in weighing the equities and determining whether the trial court properly granted the mandatory injunction.
The defendant seeks a preliminary mandatory injunction requiring plaintiff to file a claim before 12 February 1976 for a refund of $18,099.51 based on a deduction of $31,000.00 for counsel fees. A mandatory injunction requires the party enjoined to do a positive act. As a rule a. mandatory injunction will not be made as a preliminary injunction, except where the injury is immediate, irreparable and clearly established. Ingle v. Stubbins, 240 N.C. 382, 82 S.E. 2d 388 (1954). “The issuing court, after weighing the equities and the advantages and disadvantages to the parties, determines in its sound discretion whether an interlocutory injunction should be granted or refused. The court cannot go further and determine the final rights of the parties which must be reserved for the final trial *327of the action. [Citations omitted.] ‘In passing on the validity of an interlocutory injunction the appellate court is not bound by the findings of fact made by the issuing court, but may review the evidence and make its own findings. . . . ’ ” Telephone Co. v. Plastics, Inc., 287 N.C. 232, 235, 214 S.E. 2d 49, 51 (1975). The burden is upon the appellant to show error by the issuing court. Huggins v. Board of Education, 272 N.C. 33, 157 S.E. 2d 703 (1967).
In our opinion the contractual duty of the plaintiff to make a reasonable effort to pursue her claim for a refund requires that she, the only person with standing to do so, file a claim for a 1968 tax refund pursuant to the settlement proposal contained in the 4 November 1976 letter of the Chief Counsel of the Internal Revenue Service. Plaintiff does not question the authenticity of the letter which makes this proposal. In weighing the equities and the advantages and disadvantages to plaintiff and defendant, we find that the tax refund in the sum of about $18,099.51 may be irretrievably lost, to the disadvantage of defendant who was required by the 1968 separation agreement to reimburse plaintiff for the loss if she was unable to deduct the counsel fees. If the plaintiff is prejudiced in her claim for refund based on deduction of $14,500.00 in 1968 paid to her for child support and automobile, she is protected against loss by the $30,000.00 bond which the trial court required of defendant. Further, plaintiff’s action against defendant for damages for failure to reimburse her is still pending, and this decision does not determine any other right of the parties. In “balancing conveniences” we find that the preliminary mandatory injunction will restrain threatened irreparable injury to defendant’s rights, and that the plaintiff has not carried the burden of showing error by the trial court. The order of the trial court in the issuance of the preliminary mandatory injunction is
Affirmed.
Judges Morris and Vaughn concur.